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1. US20200131379 - DISPERSANT, DISPERSANT COMPOSITION, DISPERSION COMPOSITION FOR BATTERIES, ELECTRODE AND BATTERY

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[ EN ]

BACKGROUND

Technical Field

      The present invention relates to a dispersant, a dispersant composition, a dispersion composition for batteries, an electrode, and a battery.

Description of Related Art

      Carbon materials are widely used as conduction auxiliary agents in the battery field. In order to reduce resistance of a battery and obtain a high performance, a conductive path needs to be efficiently formed in an electrode by controlling the carbon material distribution with high accuracy.
      To realize the above-description, carbon materials need to be uniformly dispersed in a solution at a high concentration. However, carbon materials, which are nanoparticles with a large surface area, have strong cohesion force between themselves. Accordingly, it is difficult to manufacture a dispersion liquid that is stable not only in an initial stage but also after the elapse of time.
      Various dispersants have been actively studied to solve these problems. For example, Patent Literature 1 and Patent Literature 2 disclose a composition for batteries in which a carbon material is dispersed using polymer dispersants such as polyvinyl pyrrolidone or polyvinyl butyral.
      However, such polymer dispersants are themselves viscous. For this reason, in a case where they are used for carbon materials with a high specific surface area, such as carbon nanotubes, which are known for their high conductivity, an amount of dispersant required increases, and therefore a viscosity of a dispersion liquid may increase. As a result, coatability of a composition deteriorates, and a favorable electrode may not be obtained.
      In addition, there is a case in which polymer dispersants absorb an electrolyte solution in a battery and swell, a contact state between carbon materials, or between carbon materials and active materials or current collectors breaks, and thereby an appropriately formed conductive path is cut off. As a result, problems such as a deterioration in battery resistance and a decrease in cycle life occur.
      Furthermore, there is a problem of a deterioration in battery resistance because polymer dispersants dissolved in an electrolyte solution increase a viscosity of the electrolyte solution and decrease diffusibility of electrolyte ions. Because a viscosity increase in an electrolyte solution is particularly affected by low temperatures, the ionic resistance significantly deteriorates at a low temperature range.
      Meanwhile, Patent Literature 3 discloses a dispersion composition for batteries which is formed of dispersants in which an amine is added to an acidic derivative of a triazine. These dispersants are not viscous unlike polymer, and cause appropriate charge repulsion in a solvent such as N-methyl-2-pyrrolidone, which is an aprotic polar solvent, thereby enabling manufacture of a favorable dispersion liquid.
      Dispersants can improve a battery characteristic through formation of an efficient conductive path. Meanwhile, because the above-described dispersants are themselves insulating components, there is a limitation on raising the inherent conductivity of a carbon material to the maximum, indicating that they cannot cope with demands for further lowering resistance. In addition, it is impossible to realize a reduction in resistance components such as ionic resistance and reaction resistance, other than electrical resistance.
      Patent Literature 4 discloses a composition for batteries which is formed of triazine derivatives having an aromatic hydroxyl group or an aromatic thiol group. These derivatives are considered to impart excellent dispersion stability to carbon materials and to improve wettability of an electrolyte solution. However, the triazine derivatives of Patent Literature 4 also cannot realize a reduction in resistance components such as ionic resistance and reaction resistance, other than electrical resistance.
      In addition, as a method for obtaining a carbon material pre-treated with dispersants, a method in which dispersants are completely or partially dissolved in a basic aqueous solution to which an amine or an inorganic base is added; a carbon material is added, mixed in, and dispersed in the solution to allow these dispersants to act on (for example, be adsorbed to) the carbon material; and thereby aggregated particles are obtained by agglomeration has been disclosed. However, when adjusting a pH to be basic by adding an amine or an inorganic base to increase the solubility of dispersants, active material components are eluted, causing problems of a deterioration in battery characteristics and life, and an increase in resistance due to corrosion of a metal foil of a current collector.
      Furthermore, there is also concern that, because the dispersants of Patent Literature 3 and Patent Literature 4 are not only highly soluble in a dispersion solvent but also easily eluted in an electrolyte solution, eluted dispersants may diffuse in a battery and may adversely affect a counter electrode or separator, and surrounding members such an exterior body.
      In Patent Literature 5, a carbon material dispersion liquid is manufactured by using triazine derivatives and polyvinyl alcohol in combination as dispersants, and thereby an electrode and a secondary battery are manufactured. This can provide a dispersion liquid which has an excellent storage stability at a high concentration, and by which adhesiveness of a coated electrode (coating film) becomes favorable. However, the advantages of triazine derivatives and polyvinyl alcohol were simply combined with each other, and it is not expected that any effect beyond their respective performances would be exhibited.
      In addition, as in the triazine derivatives disclosed in Patent Literature 3 and Patent Literature 4, the triazine derivatives disclosed in Patent Literature 5 had the same problem of solubility in an electrolyte solution.
      Meanwhile, the performances required of batteries has further increased in recent years. For example, regarding mobile applications, smartphones are required to cope with more complex applications on a large screen, and despite increasing power consumption, there is demand for faster charging, a longer operation time, a thinner thickness, a smaller size, and a lower weight at the same time. In addition, in accordance with the spread of wearable terminals such as watches, yet smaller batteries having a higher energy density have become necessary. Regarding in-vehicle applications, the demand is changing from batteries for hybrid vehicles in which a high output is required but a low capacity has been allowed, to batteries for plug-in hybrid vehicles and electric vehicles in which all characteristics are required to be excellent and well-balanced.

REFERENCE LIST

Patent Literature

      Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2003-157846
      Patent Literature 2: Japanese Patent Application Laid-Open (JP-A) No. 2011-184664
      Patent Literature 3: PCT International Publication No. WO2008/108360
      Patent Literature 4: Japanese Patent Application Laid-Open (JP-A) No. 2010-61932
      Patent Literature 5: Japanese Patent Application Laid-Open (JP-A) No. 2015-101615

SUMMARY

Technical Problem

      In view of the above background, the present invention provides a dispersant which has favorable dispersibility and reduces electrical resistance as compared to dispersants of the related art; and a battery in which ionic resistance and reaction resistance are reduced through use of this dispersant, and thereby has excellent characteristics.

Solution to Problem

      As a result of intensive studies, the inventors of the present invention have found that, by using a dispersant including a triazine derivative having a specific structure, and an amine or an inorganic base, a favorable conductive path is formed, and thereby not only electrical resistance can be reduced but also the ionic resistance and reaction resistance can be reduced. Accordingly, the present invention has been completed.
      That is, the present invention relates to a dispersant including a triazine derivative represented by General Formula (1), and an amine or an inorganic base.

(MOL) (CDX)
      [In General Formula (1), R 1 is a group represented by —X 1—Y 1, where X 1 is an arylene group which may have a substituent, and Y 1 is a sulfo group or a carboxyl group; or
      R 1 is a phenyl group having a substituent containing at least —NHC(═O)—, a benzimidazole group, an indole group which may have a substituent, or a pyrazole group which may have a substituent.]
      In one aspect of the dispersant, a content of the amine with respect to the triazine derivative is 0.1 to 5 molar equivalents.
      In one aspect of the dispersant, a content of the amine with respect to the triazine derivative is 0.3 to 2 molar equivalents.
      In one aspect of the dispersant, a content of the inorganic base with respect to the triazine derivative is 0.1 to 1 molar equivalent.
      The present invention relates to a dispersion composition including the above-described dispersant and a polymer dispersant.
      In one aspect of the dispersion composition, the polymer dispersant has a hydroxyl group.
      In one aspect of the dispersion composition, a polyvinyl alcohol resin and/or a cellulose resin.
      The present invention relates to a dispersion composition including the above-described dispersant, a carbon material, and a solvent.
      The present invention relates to a dispersion composition including the above-described dispersant composition, a carbon material, and a solvent.
      One aspect of the dispersion composition further includes a binder.
      The present invention relates to a dispersion composition for batteries, in which the above-described dispersion composition further contains an active material.
      In one aspect of the dispersion composition for batteries, a content of a dispersant containing a triazine derivative, and an amine or an inorganic base is 0.1 to 200 mg with respect to a 1 m 2 surface area of the active material.
      The present invention relates to an electrode including a mixture layer formed from the above-described dispersion composition for batteries on a current collector.
      The present invention relates to a battery including the above-described electrode and a non-aqueous electrolyte solution.
      In one aspect of the battery, a content of a dispersant containing a triazine derivative, and an amine or an inorganic base is 10 μg to 60 mg with respect to 1 ml of the non electrolyte solution.

Advantageous Effects of Invention

      According to the present invention, it is possible to provide a dispersant which has favorable dispersibility and reduces electrical resistance; and a battery in which ionic resistance and reaction resistance are reduced through use of this dispersant, and thereby has excellent characteristics.

DESCRIPTION OF EMBODIMENTS

      Hereinafter, a dispersant, a dispersant composition, a dispersion composition for batteries, an electrode, and a battery according to the present invention will be described in detail in order.
      In the present invention, “(meth)acryl” means “acryl” or “methacryl.”
      <Dispersant>
      A dispersant according to the present invention includes a triazine derivative represented by General Formula (1), and an amine or an inorganic base.

(MOL) (CDX)
      [In General Formula (1), R 1 is a group represented by —X 1—Y 1, where X 1 is an arylene group which may have a substituent, and Y 1 is a sulfo group or a carboxyl group; or
      R 1 is a phenyl group having a substituent containing at least —NHC(═O)—, a benzimidazole group, an indole group which may have a substituent, or a pyrazole group which may have a substituent.]
      In the following description, unless otherwise specified, the “dispersant” means the above-described dispersant, and is distinguished from a polymer dispersant.
      The inventors of the present invention have found that, using a dispersion composition which is formed of a dispersant including a triazine derivative that has a specific structure and is represented by General Formula (1), and including an amine or an inorganic base, a favorable conductive path is formed, and thereby not only electrical resistance can be reduced but also the ionic resistance and reaction resistance can be reduced. Accordingly, the present invention has been completed.
      According to the present invention, it is possible to manufacture a battery having lower ionic resistance and reaction resistance, and an excellent rate characteristic and low-temperature characteristics, compared with a case of using known dispersion compositions of the related art.
      In addition, because the dispersant including a triazine derivative represented by General Formula (1), and an amine or an inorganic base has low solubility, elution into an electrolyte solution is inhibited. The reason for this is thought to be that crystallinity is improved, and solubility is reduced due to a structure having storing hydrogen bonding properties, in which —NH—R 1 and two hydroxyl groups are directly connected to one triazine ring. In addition, because strong interactions such as hydrogen bonding occur easily, it is considered that sufficient dispersibility can be exhibited even though the dispersant easily acts on carbon materials and has low solubility in a dispersion liquid.
      In General Formula (1),
      R 1 is a group represented by —X 1—Y 1, where X 1 is an arylene group which may have a substituent, and Y 1 is a sulfo group or a carboxyl group; or
      R 1 is a phenyl group having a substituent containing at least —NHC(═O)—, a benzimidazole group, an indole group which may have a substituent, or a pyrazole group which may have a substituent.
      “Substituents” of an arylene group, as X 1, which may have a substituent may be the same as or different from each other, and specific examples thereof include a sulfo group, a carboxyl group, a hydroxyl group, a halogen group such as fluorine, chlorine, and bromine, a nitro group, an alkyl group, an alkoxyl group, and the like. In addition, there may be a plurality of these substituents.
      Examples of “arylene groups” for the arylene group which may have a substituent include a phenylene group, a naphthylene group, and the like.
      Examples of substituents containing —NHC(═O)— in R 1 include the following structures. Here, a mark “*” represents a bonding site with a benzene ring.

(MOL) (CDX)
      In addition, a phenyl group having a substituent containing at least —NHC(═O)— may have a methyl group, a trifluoromethyl group, a methoxy group, an ethoxy group, a halogen group such as fluorine and chlorine, and the like, as other substituents. Furthermore, there may be a plurality of these substituents.
      Examples of substituents of an indole group which may have a substituent, or a pyrazole group which may have a substituent, which are R 1, include a methyl group.
      In addition, examples of amines added to triazine derivatives include primary, secondary, and tertiary alkylamines having 1 to 40 carbon atoms.
      Examples of primary alkylamines having 1 to 40 carbon atoms include propylamine, butylamine, isobutylamine, octylamine, 2-ethylhexylamine, laurylamine, stearylamine, oleylamine, 2-aminoethanol, 3-aminopropanol, 3-ethoxypropylamine, 3-lauryloxypropylamine, and the like.
      Examples of secondary alkylamines having 1 to 40 carbon atoms include dibutylamine, diisobutylamine, N-methylhexylamine, dioctylamine, distearylamine, 2-methylaminoethanol, and the like.
      Examples of tertiary alkylamines having 1 to 40 carbon atoms include triethylamine, tributylamine, N,N-dimethylbutylamine, N,N-diisopropylethylamine, dimethyloctylamine, trioctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dilaurylmonomethylamine, triethanolamine, 2-(dimethylamino)ethanol, and the like.
      Among them, primary, secondary, or tertiary alkylamines having 1 to 30 carbon atoms are preferable, and primary, secondary, or tertiary alkylamines having 1 to 20 carbon atoms are more preferable.
      An added amount of amines used in the present invention is not particularly limited, but it is preferably 0.1 to 5 molar equivalents, and is more preferably 0.3 to 2 molar equivalents with respect to the triazine derivative represented by General Formula (1).
      Amines can be added at the time of manufacturing the dispersant and/or at the time of manufacturing a composition for batteries.
      Examples of inorganic bases added to triazine derivatives include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal phosphates, alkaline earth metal phosphates, and the like.
      Examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, and the like.
      Examples of alkaline earth metal hydroxides include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, and the like.
      Examples of alkali metal carbonates include lithium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and the like.
      Examples of alkaline earth metal carbonates include magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, and the like.
      Examples of alkali metal phosphates include lithium phosphate, trisodium phosphate, disodium hydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, and the like.
      Examples of alkaline earth metal phosphates include magnesium phosphate, calcium phosphate, strontium phosphate, barium phosphate, and the like.
      An added amount of inorganic base used in the present invention is not particularly limited, but it is preferably 0.1 mol to 1.0 mol, and is more preferably 0.3 mol to 0.7 mol with respect to 1 mol of the triazine derivative represented by General Formula (1).
      Inorganic bases can be added at the time of manufacturing the dispersant and/or at the time of manufacturing a composition for batteries.
      The dispersant of the present invention can be suitably used as a dispersant particularly for carbon materials such as carbon black used for batteries, condensers, and capacitors, and it can also be used as a dispersant for pigments used in various coloring compositions such as inks, paints, and color filter resists.
      [Dispersant Composition]
      A dispersant composition of the present invention contains the above-described dispersant and a polymer dispersant.
      The inventors of the present invention have found that, when the dispersant containing the triazine derivative represented by General Formula (1) is used in combination with a polymer dispersant, a synergistic effect that specifically improves adhesiveness (peeling strength) between carbon materials, and between carbon materials and active materials or current collectors can be obtained. In addition, they also have found that use in combination can curb electrode peeling and deterioration during repeated charging and discharging over a long period of time, and thereby cycle characteristics can be improved. Furthermore, they also have found that a dispersion composition for batteries, which is formed of the triazine derivative represented by General Formula (1) and the polymer dispersant, not only can reduce electrical resistance but also can reduce the ionic resistance and reaction resistance through formation of a favorable conductive path.
      Furthermore, by using the polymer dispersant in combination, film formability and film hardness can be adjusted, or rheological control can be performed.
      <Polymer Dispersant>
      For the polymer dispersant used in the present invention, it is possible to use a polyvinyl alcohol with functional groups other than a hydroxyl group, for example, a modified polyvinyl alcohol having an acetyl group, a sulfo group, a carboxyl group, a carbonyl group, or an amino group; polyvinyl alcohols modified with various salts; polyvinyl alcohols modified with an anion or a cation; acetal-modified (for example, acetoacetal-modified or butyral-modified, and the like) polyvinyl alcohol resins which are modified by aldehydes; various (meth)acrylic polymers; polymers derived from ethylenically unsaturated hydrocarbons; various cellulose resins; and the like; and copolymers thereof, but examples are not limited thereto. Among them, the polymer dispersant in the present invention is preferably a polyvinyl alcohol resin and/or a cellulose resin. The polymer dispersants can be used alone or in combination of two or more kinds thereof.
      In addition, among them, the polymer dispersant in the present invention preferably has a hydroxyl group. An effect of combining the above-described dispersant and the polymer dispersant was particularly remarkable in a case where the polymer dispersant had a hydroxyl group. Although principles thereof are not clear, the reason for this is thought to be that strong intermolecular forces such as hydrogen bonding acted between the dispersant and the polymer dispersant.
      An average degree of polymerization of polymer dispersants is preferably 50 to 3000, is particularly preferably 100 to 2000, and is even more preferably 200 to 1000, because when it is too low, the strength of adsorption to dispersoids is weak, and when it is too high, not only does a viscosity increase, but also a dispersion stabilization effect is diminished because polymer dispersants do not spread favorably in a dispersion liquid.
      In the polyvinyl alcohol resin, there is preferably 60 mol % or more of hydroxyl groups, more preferably 70 mol % or more, and even more preferably 75 mol % or more, in order to impart an appropriate affinity with a dispersoid, a dispersion solvent, and an electrolyte solution.
      As commercially available polyvinyl alcohol resins in which an amount of hydroxyl groups falls within the above-described range, it is possible to obtain various grades, for example, KURARAY POVAL (a polyvinyl alcohol resin manufactured by Kuraray Co., Ltd.), GOHSENOL and GOHSENX (a polyvinyl alcohol resin manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), DENKA POVAL (a polyvinyl alcohol resin manufactured by Denka Company Limited), J-POVAL (a polyvinyl alcohol resin manufactured by Japan Vam & Poval Co., Ltd.), and the like (all of which are trade names). In addition, modified polyvinyl alcohols having various functional groups are also available.
      It is known that, in a case of synthesizing without using commercially available products, in general, vinyl acetate is polymerized to a specified degree of polymerization in a methanol solution or the like, an alkali catalyst such as sodium hydroxide is added to the obtained polyvinyl acetate, and saponification reaction is performed, thereby polyvinyl alcohol in which an amount of hydroxyl group is controlled can be obtained.
      It is known that, in a case where modified polyvinyl alcohol is synthesized and used, in general, vinyl acetate is copolymerized with (meth)acrylic monomers such as (meth)acrylic acid, vinyl ester monomers, monomers having α-β unsaturated bonds and functional groups, and the like in a methanol solution or the like, and then saponification reaction is performed, and thereby modified polyvinyl alcohol in which a modification rate is controlled can be obtained. In addition, a modified polyvinyl alcohol resin can be obtained by adding an acid anhydride to a polyvinyl alcohol resin to react them, or by esterification reaction thereof.
      As commercially available polyvinyl acetal resins, various grades are available under the trade names such as MOWITAL (a polyvinyl butyral resin manufactured by Kuraray Co., Ltd.), and S-LEC (polyvinyl acetal or polyvinyl butyral manufactured by SEKISUI CHEMICAL CO., LTD.), but a polyvinyl acetal resin may be synthesized and used in order to obtain the above-described preferable amount of hydroxyl groups. As a general synthesis method, it is possible to obtain a polyvinyl acetal resin controlled to a predetermined degree of acetalization by reacting polyvinyl alcohol with an aldehyde. In addition, the carbon number of an acetal group can be arbitrarily selected by changing the carbon number of aldehyde.
      As cellulose resins, it is possible to use cellulose; cellulose in which a hydroxyl group is partially modified with an alkyl group, hydroxyalkyl group, or carboxyalkyl group; or salts thereof. For example, various grades are available under the trade names such as METOLOSE (methylcellulose or hydroxypropylmethylcellulose manufactured by Shin-Etsu Chemical Co., Ltd.), Mecellose (water-soluble cellulose ether, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, and methylcellulose manufactured by TOMOE KOGYO CO., LTD.), SUNROSE (carboxymethylcellulose sodium manufactured by Nippon Paper Industries Co., Ltd.), ETHOCEL (ethyl cellulose manufactured by Dow Chemical Company), and DAICEL-CMC (carboxymethylcellulose sodium manufactured by Daicel FineChem Ltd.). In particular, alkylcelluloses such as methylcellulose and ethylcellulose are preferable from the viewpoints of solubility in an electrolyte solution and swellable ability.
      [Dispersion Composition]
      The dispersion composition of the present invention contains the dispersant or the dispersant composition, a carbon material, and a solvent.
      The carbon material used in the present invention is not particularly limited, but in a case of being used as a carbon material for batteries, graphite, carbon black, carbon nanotube, carbon nanofiber, carbon fiber, graphene, fullerene, and the like are preferably used alone or in combination of two or more kinds thereof. In a case of being used as a carbon material, it is preferable to use carbon black from the viewpoints of conductivity, availability, and cost.
      As the carbon black used in the present invention, commercially available various carbon blacks such as furnace black, channel black, thermal black, acetylene black, and ketjenblack can be used alone or in combination of two or more kinds thereof. In addition, carbon black subjected to oxidization, which is generally performed, hollow carbon, and the like can also be used. Furthermore, a particle diameter of carbon black is preferably 0.01 to 1 μm and is more preferably 0.01 to 0.2 μm. The particle diameter referred herein means an average primary particle diameter measured with an electron microscope, and this physical property value is generally used to represent physical characteristics of carbon black.
      The carbon nanotube used in the present invention is a carbon material having a shape in which graphene is wound into a cylindrical shape. A diameter obtained by observation with an electron microscope is about several nm to 100 nm, and a length is about several nm to 1 mm. In order to exhibit semiconductor characteristics, transparency of a coating film, and the like, the diameter is preferably 50 nm or less and is particularly 20 nm or less. The length is preferably 100 nm to 1 mm and is particularly preferably 500 nm to 1 mm. There are single-walled carbon nanotubes, and carbon nanotubes having a multilayer structure, but any structure may be used. In addition, it is also possible to use carbon nanotubes which are classified as carbon nanofibers, and have a fiber diameter of about 100 nm to 1 μm which is obtained by observation with an electron microscope.
      The graphene used in the present invention is a monoatomic thin film constituting graphite, and is a carbon material in which carbon atoms are arranged in a honeycomb lattice (a hexagonal shape) on a flat surface, and this includes a multi-layered graphene. As the multi-layered graphene, a multi-layered graphene having 2 to 50 graphene layers can be used.
      <Solvent>
      The solvent used in the present invention may be an aprotic polar solvent and a water-soluble polar solvent, and one kind thereof may be used in water, or two or more kinds thereof may be mixed and used in water. The aprotic polar solvent is preferably an amide solvent. It is particularly preferable to use amide aprotic solvents such as N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, and hexamethylphosphoric triamide. The water-soluble polar solvent is preferably alcohol-based, ester-based, ether-based, glycol-based, glycol ester-based, or glycol ether-based. Water may be used alone, and a small amount of water-soluble polar solvent with low surface tension may be used in combination to improve wettability and coatability of carbon materials. It is particularly preferable to use water in combination with propylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol dimethyl ether, propylene glycol monopropyl ether, and N-methyl-2-pyrrolidone.
      <Binder>
      The dispersion composition of the present invention may further contain a binder. The binder to be used is not particularly limited, but examples thereof include polymers or copolymers containing, as constitutional units, ethylene, propylene, vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic ester, methacrylic acid, methacrylic acid esters, acrylonitrile, styrene, vinyl butyral, vinyl acetal, vinyl pyrrolidone, and the like, a polyurethane resin, a polyester resin, a phenol resin, an epoxy resin, a phenoxy resin, a urea resin, a melamine resin, an alkyd resin, an acrylic resin, a formaldehyde resin, a silicone resin, a fluorine resin, cellulose resins such as carboxymethylcellulose, rubbers such as a styrene-butadiene rubber and a fluorine rubber, conductive resins such as polyaniline and polyacetylene, and the like. In addition, modified products and copolymers of these resins may be used. In particular, when being used for battery applications, it is preferable to use a polymer compound containing a fluorine atom in a molecule, for example, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene, and the like, from the viewpoint of resistance. These binders can be used alone or a plurality of binders may be combined and used. Furthermore, in a case of using water as a solvent, it is preferable to use, in combination, polymer compounds containing fluorine atoms and emulsions such as styrene-butadiene rubber, and carboxymethylcellulose which also functions as a thickener.
      The dispersion composition of the present invention is a carbon material dispersion liquid containing the above-described dispersant, a carbon material, and a solvent, or a carbon material dispersion varnish containing a binder, and can be used in fields such as printing inks, paints, plastics, toners, color filter resist inks, and batteries in which uniform and favorable coating properties are required. In particular, because the dispersion composition can provide a coating film suitable for an electrode layer having a uniform and favorable coating properties and a low surface resistance, the dispersion composition can be suitably used for forming an electrode for batteries. The dispersion composition may be used for a base layer provided between a current collector and a mixture layer.
      <Method for Producing Dispersion Composition>
      The carbon material dispersion liquid which is the dispersion composition of the present invention can be manufactured by mixing the above-described dispersant or dispersant composition, the carbon material, and a solvent. In addition, the carbon material dispersion varnish can be manufactured by mixing the above-described dispersant or dispersant composition, the carbon material, a solvent, and a binder. The order of addition of each component is not limited, and for the case of the carbon material dispersion liquid, examples thereof include (1) method of mixing and dispersing all components at once; (2) method of dispersing a carbon material in a solvent in which a dispersant or a dispersant composition is dispersed and dissolved in advance; and the like. In addition, for the case of the carbon material dispersion varnish, examples of orders of addition include (1) method of mixing, dispersing, and dissolving all components at once; (2) method of mixing and dissolving a binder powder after producing a carbon material dispersion liquid in advance; (3) method of mixing a binder solution after producing a carbon material dispersion liquid in advance; and the like. Furthermore, the above-described solvent may be further added as needed.
      As a mixing/dispersing/dissolving device, a dispersing device generally used for pigment dispersion or the like can be used. For example, mixers such as dispersers, homomixers, planetary mixers; homogenizers (“Clare mix” manufactured by M Technique, “Fillmix” and the like manufactured by PRIMIX, “Abramix” and the like manufactured by Silverson); paint conditioners (manufactured by Red Devil); colloid mills (“PUC colloid mill” manufactured by PUC, “Colloid Mill MK” manufactured by IKA); corn mills (“Cone Mill MKO” and the like manufactured by IKA); ball mills; sand mills (“Dynomill” and the like manufactured by Shinmaru Enterprises); attritors; pearl mills (“DCP mill” and the like manufactured by Eirich); media-type dispersers such as coball mills; wet jet mills (“Genus PY” manufactured by Genus, “Starburst” manufactured by Sugino Machine, “Nanomizer” manufactured by Nanomizer, and the like); “Claire SS-5” manufactured by M Technique; media-less dispersers such as “MICROS” manufactured by Nara Machinery Co., Ltd.; other roll mills; and the like, but examples are not limited thereto.
      In addition, it is preferable to use a disperser that has been treated to prevent metal contamination from the disperser. As metal contamination prevention treatment, for example, when using a media-type disperser, it is preferable to use a method in which disperser with an agitator and a vessel made of ceramic or resin is used, or to use a metal agitator and a disperser in which a surface of a vessel is treated with tungsten carbide spraying, resin coating, or the like. As the media, it is preferable to use glass beads, ceramic beads such as zirconia beads or alumina beads. In addition, when using a roll mill, it is preferable to use a ceramic roll. Only one type of disperser may be used, or multiple types of devices may be used in combination.
      [Dispersion Composition for Batteries]
      The dispersion composition for batteries of the present invention is a dispersion composition for batteries in which the above-described dispersion composition further contains an active material.
      <Active Material>
      The active material is a substance that charges or discharges a battery with a redox reaction in the battery. Examples thereof include a cathode active material used for a cathode and an anode active material used for an anode.
      (Cathode Active Material)
      The cathode active material to be used is not particularly limited as long as it functions as a battery active material. For example, when being used in a lithium ion secondary battery, metal oxides capable of doping or intercalating lithium ions, metal compounds such as metal sulfides, conductive polymers, and the like can be used.
      Specific examples thereof include powders of complex oxides of lithium and transition metal, such as a lithium manganese composite oxide (for example, Li xMn 2O 4 or Li xMnO 2), a lithium nickel composite oxide (for example, Li xNiO 2), a lithium cobalt composite oxide (Li xCoO 2), a lithium nickel cobalt composite oxide (for example, Li xNi 1−yCo yO 2), a lithium manganese cobalt composite oxide (for example, Li xMn yCo 1−y−zO 2), a lithium nickel manganese cobalt composite oxide (for example, Li xNi yCo zMn 1−y−zO 2), and a spinel-type lithium manganese nickel composite oxide (for example, Li xMn 2−yNi yO 4); powders of lithium phosphorus oxides having an olivine structure (for example, Li xFePO 4, LiFe 1−yMn yPO 4, LiCoPO 4, and the like); powders of transition metal oxides such as a manganese oxide, an iron oxide, a copper oxide, a nickel oxide, a vanadium oxide (for example, V 2O 5, V 6O 13), and a titanium oxide; powders of transition metal sulfides such as iron sulfate (Fe 2(SO 4) 3), TiS 2, and FeS; and the like. Where, x, y, and z are numbers, and 0<x<1, O<y<1, 0<z<1, 0<y+z<1. In addition, conductive polymers such as polyaniline, polyacetylene, polypyrrole, and polythiophene can also be used. These cathode active materials can be used alone or in combination.
      (Anode Active Material)
      Anode active materials to be used are not particularly limited, but Li metal that can be doped or intercalated with lithium ions, or its alloys, tin alloys, silicon alloy anodes, metal oxides such as Li xTiO 2, Li xFe 2O 3, Li xFe 3O 4, Li xWO 2, conductive polymers such as polyacetylene and poly-p-phenylene, carbonaceous powders of artificial graphite such as amorphous carbonaceous materials such as soft carbon and hard carbon and highly graphitized carbon material, or natural graphite, and carbon-based materials such as carbon black, mesophase carbon black, resin-fired carbon material, vapor layer-grown carbon fiber, and carbon fiber are used. Where, x is a number, and 0<x<1. These anode active materials can be used alone or in combination.
      In the dispersion composition for batteries, a content of the dispersant is preferably 0.1 to 200 mg, is more preferably 0.2 to 100 mg, and is even more preferably 0.5 to 50 mg with respect to a 1 m 2 the active material surface area.
      The dispersion composition for batteries of the present invention is a carbon material dispersion liquid containing the above-described composition for batteries, a carbon material, and a solvent, or a carbon material dispersion varnish containing a binder, and can be used in fields such as printing inks, paints, plastics, toners, color filter resist inks, and batteries in which uniform and favorable coating properties are required. In particular, because the dispersion composition can provide a coating film suitable for an electrode layer having a uniform and favorable coating properties and a low surface resistance, the dispersion composition can be suitably used for forming an electrode for batteries. The dispersion composition can be used for a base layer provided between a current collector and a mixture layer.
      The dispersion composition for batteries is preferably used as a dispersion composition for batteries (hereinafter referred to as a “mixture paste”) in which an active material is contained in a dispersion composition for batteries containing the above-described dispersant or dispersant composition, a carbon material, a solvent, and a binder.
      This mixture paste can be produced by mixing the above-described dispersant, a carbon material, a solvent, a binder, and an active material. The order of addition of each component is not limited. Examples thereof include a method of mixing all components at once; a method in which the remaining components are added to and mixed with a carbon material dispersion liquid produced in advance by the above-described method; a method in which an active material is added to and mixed with a carbon material dispersion varnish produced in advance by the above-described method; and the like. Furthermore, the above-described solvent may be further added as needed.
      As a device for manufacturing the mixture paste, the same device as used in manufacturing the dispersion composition described above can be used.
      [Electrode and Battery]
      The electrode according to the present invention includes a mixture layer formed from the above-described dispersion composition for batteries on a current collector.
      In addition, the battery according to the present invention includes the electrode and a non-aqueous electrolyte solution.
      The dispersion composition for batteries of the present invention can be suitably used particularly for a lithium ion secondary battery. Hereinafter, a lithium ion secondary battery will be described as an example. However, a battery formed of the dispersion composition for batteries is not limited to a lithium ion secondary battery.
      A lithium ion secondary battery includes a cathode having a cathode mixture layer on a current collector, an anode having an anode mixture layer on the current collector, and a non-aqueous electrolyte solution formed of an electrolyte containing lithium.
      Regarding the electrode, materials and shapes of the current collector to be used are not particularly limited. As materials thereof, metals such as aluminum, copper, nickel, titanium, and stainless steel, and alloys thereof are used, but in particular, it is preferable to use aluminum as a cathode material, and copper as an anode material. In addition, as shapes, foil on a flat plate is generally used, but a roughened surface, a perforated foil shape, and a mesh shape can also be used. Furthermore, the current collector may have a conductive underlayer for the purpose of improving contact resistance and adhesiveness between the current collector and the mixture layer.
      The mixture layer can be formed by applying the above-described mixture paste directly on the current collector and drying. A thickness of the mixture layer is generally 1 μm to 1 mm, and is preferably 100 μm to 500 μm. A coating method therefor is not particularly limited, and a well-known method can be used. Specific examples thereof include a die coating method, a dip coating method, a roll coating method, a doctor coating method, a spray coating method, a gravure coating method, a screen printing method, an electrostatic coating method, and the like. In addition, rolling treatment by a lithographic press, a calender roll, and the like after application may be performed.
      In the battery of the present invention, a content of the dispersant is preferably 10 μg to 60 mg, is more preferably 50 μg to 20 mg, and is even more preferably 70 μg to 15 mg with respect to 1 ml of the non electrolyte solution.
      As the electrolyte solution that constitutes the lithium ion secondary battery, an electrolyte solution in which an electrolyte containing lithium is dissolved in a non-aqueous solvent is used. Examples of electrolytes include LiBF 4, LiClO 4, LiPF 6, LiAsF 6, LiSbF 6, LiCF 3SO 3, Li(CF 3SO 2) 2N, LiC 4F 9SO 3, Li(CF 3SO 2) 3C, LiI, LiBr, LiCl, LiAlCl, LiHF 2, LiSCN, LiBPh 4 (where Ph is a phenyl group), and the like, but examples are not limited thereto.
      A non-aqueous solvent is not particularly limited, but examples thereof include carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate; lactones such as γ-butyrolactone, γ-valerolactone, and γ-octanoic lactone; glymes such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, and 1,2-dibutoxyethane; esters such as methyl formate, methyl acetate, and methyl propionate; sulfoxides such as dimethyl sulfoxide and sulfolane; nitriles such as acetonitrile; n-methyl-2-pyrrolidone; and the like. These solvents may be used alone or in combination of two or more kinds thereof. In particular, it is preferable to mix ethylene carbonate having a high dielectric constant and high electrolyte dissolving power with other solvents. Furthermore, as other solvents, linear carbonate solvents such as propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate are more preferable.
      Furthermore, the above-described electrolyte solution can be held in a polymer matrix to form a gel polymer electrolyte. Examples of polymer matrix include an acrylate resin having a polyalkylene oxide segment, a polyphosphazene resin having a polyalkylene oxide segment, a polysiloxane having a polyalkylene oxide segment, and the like, but examples are not limited thereto.
      A structure of the battery of the present invention is not particularly limited, but it is generally composed of a cathode and an anode, and a separator provided as necessary. As shapes, various shapes such as paper type, cylindrical type, square type, button type, laminated type, and winding type can be adopted according to the purpose of use.

OTHER EMBODIMENTS

      In a case where the triazine derivative represented by General Formula (1) has an acidic functional group, it can be used as a dispersant by combining with the polymer dispersant even when it does not have an amine or an inorganic base. That is, as one embodiment of the dispersant composition, a dispersant composition containing the triazine derivative having an acidic functional group represented by General Formula (1), and a polymer dispersant may be adopted. In this case, in General Formula (1), R 1 is a group represented by —X 1—Y 1, in which X 1 represents an arylene group which may have a substituent, and Y 1 represents a sulfo group or a carboxyl group.
      In each configuration of the present invention, the dispersant composition of the present embodiment can be used instead of the dispersant composition of the present invention.

EXAMPLES

      Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, in order to clarify differences between respective compositions, a dispersion composition composed of a dispersant, a carbon material, and a solvent is referred to as a “carbon material dispersion liquid,” a dispersion composition composed of a dispersant, a carbon material, a solvent, and a binder is referred to as “carbon material dispersion varnish,” and a dispersion composition for batteries composed of a dispersant, a carbon material, a solvent, a binder, and an active material is referred to as a “mixture paste.” Furthermore, unless otherwise specified, N-methyl-2-pyrrolidone used as a solvent is abbreviated as “NMP,” and % by mass is abbreviated as “%.”
      Hereinafter, examples will be explained in three separate example groups. Each example group is independent, and the same abbreviation may be given to different dispersants among the example groups.
      Because materials other than dispersants are common to the three example groups, they will be described below, and their descriptions will be omitted in each example group.
      <Carbon Material>
      DENKA BLACK HS100 (manufactured by Denka Company Limited): Acetylene black, in which an average primary particle diameter obtained by observation with an electron microscope is 48 nm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 39 m 2/g (hereinafter abbreviated as “HS100”).
      super-P (manufactured by TIMCAL): Furnace black, in which an average primary particle diameter obtained by observation with an electron microscope is 40 nm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 62 m 2/g.
      MONARCH 800 (manufactured by Cabot Corporation): Furnace Black, in which an average primary particle diameter obtained by observation with an electron microscope is 17 nm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 210 m 2/g (hereinafter abbreviated as “M800”).
      EC-300J (manufactured by LION SPECIALTY CHEMICALS CO., LTD.): KETJENBLACK, in which an average primary particle diameter obtained by observation with an electron microscope is 40 nm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 800 m 2/g.
      Carbon nanotubes: Multi-layered carbon nanotubes, in which a fiber diameter is 10 nm and a fiber length is 2 to 5 μm, which are obtained by observation with an electron microscope, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 600 m 2/g (hereinafter abbreviated as CNT).
      VGCF (manufactured by Showa Denko K. K.): Carbon nanofibers, in which a fiber diameter is 150 nm and a fiber length is 10 to 20 μm, which are obtained by observation with an electron microscope.
      <Binder>
      KF Polymer W1100 (manufactured by Kureha Corporation): Polyvinylidene fluoride (PVDF), hereinafter abbreviated as PVDF.
      Polytetrafluoroethylene emulsion: (manufactured by Du Pont-Mitsui Fluorochemicals Co., Ltd.), hereinafter abbreviated as PTFE.
      Carboxymethylcellulose (manufactured by Nippon Paper Industries Co., Ltd.): hereinafter abbreviated as CMC.
      <Cathode Active Material>
      LiNi 1/3Mn 1/3Co 1/3O 2 (manufactured by TODA KOGYO CORP.): Cathode active material, lithium nickel manganese cobalt oxide, in which an average primary particle diameter obtained by observation with an electron microscope is 5.0 μm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 0.62 m 2/g (hereinafter abbreviated as NMC).
      HLC-22 (manufactured by Honjo Chemical Corporation): Cathode active material, lithium cobalt oxide (LiCoO 2), in which an average primary particle diameter obtained by observation with an electron microscope is 6.6 μm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 0.62 m 2/g (hereinafter abbreviated as LCO).
      LiNi 0.8Co 0.15Al 0.05O 2 (manufactured by Sumitomo Metal Mining Co., Ltd.): Cathode active material, lithium nickel cobalt aluminate, in which an average primary particle diameter obtained by observation with an electron microscope is 5.8 μm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 0.38 m 2/g (hereinafter abbreviated as NCA).
      LiFePO 4 (manufactured by Clariant): Cathode active material, lithium iron phosphate, in which an average primary particle diameter obtained by observation with an electron microscope is 0.4 μm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 15.3 m 2/g (hereinafter abbreviated as LFP).
      <Anode Active Material>
      Spheroidal graphite (manufactured by Nippon Graphite Industries, Co., Ltd.): Anode active material, in which a primary particle diameter obtained by observation with an electron microscope is 15 μm, and a specific surface area obtained by an S-BET formula from a nitrogen adsorption amount is 1.0 m 2/g (hereinafter abbreviated as spheroidal graphite).
      <Polymer Dispersant>
      PVA-103 (manufactured by Kuraray Co., Ltd.): Polyvinyl alcohol, in which a degree of saponification is 98.0 to 99.0 mol %, and an average degree of polymerization is 300.
      PVA-403 (manufactured by Kuraray Co., Ltd.): Polyvinyl alcohol, in which a degree of saponification is 78.5 to 81.5 mol %, and an average degree of polymerization is 300.
      KL-506 (manufactured by Kuraray Co., Ltd.): Anion-modified polyvinyl alcohol, in which a degree of saponification is 74.0 to 80.0 mol %, and a degree of polymerization is 600.
      GOHSENX L-3266 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.): Sulfonic-acid-modified polyvinyl alcohol, in which a degree of saponification is 86.5 to 89.0 mol % (hereinafter abbreviated as L-3266).
      GOHSENX K-434 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.): Cation-modified polyvinyl alcohol, in which a degree of saponification is 85.5 to 88.0 mol % (hereinafter abbreviated as K-434).
      Polyvinyl butyral A: Polyvinyl butyral, in which a degree of butyralization is 15 mol %, a content of hydroxyl groups is 84 mol %, a content of acetic acid groups is 1 mol %, and a degree of polymerization is 300 (hereinafter abbreviated as PVB-A).
      METOLOSE SM-15 (manufactured by Shin-Etsu Chemical Co., Ltd.): Methyl cellulose, in which a degree of substitution is 1.8, and a viscosity of a 2% aqueous solution at 20° C. is about 15 mPa·s (hereinafter abbreviated as SM-15).
      ETHOCEL 10 (manufactured by Dow Chemical Company): Ethyl cellulose, in which a viscosity of a 5% toluene/ethanol (8/2) solution at 25° C. is 9.0 to 11.0 mPa·s.

(Synthesis Example) Synthesis of PVB-A

      A 10% aqueous solution of PVA-103 was prepared, and 0.2 parts by mass of hydrochloric acid and 2 parts by mass of butylaldehyde were added dropwise to 100 parts by mass of the aqueous solution while stirring. Subsequently, a temperature was raised to 80° C., held for 1 hour, and then cooling was allowed. This mixture was dried and pulverized, and thereby PVB-A having a 15 mol % degree of acetalization was obtained.

First Example Group

      In First Example Group, among the triazine derivatives represented by General Formula (1), a triazine derivative in which R 1 is a group represented by —X 1—Y 1, where X 1 is an arylene group which may have a substituent, and Y 1 is a sulfo group or a carboxyl group will be described.
      <Dispersant>
      Structures of the triazine derivatives A to T represented by General Formula (1) of the present invention are shown below. A method for manufacturing the triazine derivatives A to T represented by General Formula (1) used in the present invention is not particularly limited, and a well-known method can be applied. For example, a method described in JP2004-217842A can be applied. The disclosure by the above publication is partially incorporated in the present specification by reference.

(MOL) (CDX)
(MOL) (CDX)
(MOL) (CDX)
(MOL) (CDX)
      <Method for Manufacturing Dispersant Composed of Triazine Derivative and Amine>
      Dispersants a to aj shown in Table 1 were manufactured by methods described in the following examples.
[TABLE-US-00001]
TABLE 1
 
        Molar equivalent
        of amine with
        respect to triazine
  Dispersant Triazine derivative Inorganic base derivative
 
Example A1-1 a Triazine derivative A Octylamine 1.0
Example A1-2 b Triazine derivative B Octylamine 1.0
Example A1-3 c Triazine derivative C Octylamine 1.0
Example A1-4 d Triazine derivative D Octylamine 1.0
Example A1-5 e Triazine derivative E Octylamine 1.0
Example A1-6 f Triazine derivative F Octylamine 1.0
Example A1-7 g Triazine derivative G Octylamine 1.0
Example A1-8 h Triazine derivative H Octylamine 1.0
Example A1-9 i Triazine derivative I Octylamine 1.0
Example A1-10 j Triazine derivative J Octylamine 1.0
Example A1-11 k Triazine derivative K Octylamine 1.0
Example A1-12 l Triazine derivative L Octylamine 1.0
Example A1-13 m Triazine derivative M Octylamine 1.0
Example A1-14 n Triazine derivative N Octylamine 1.0
Example A1-15 o Triazine derivative O Octylamine 1.0
Example A1-16 p Triazine derivative P Octylamine 1.0
Example A1-17 q Triazine derivative Q Octylamine 1.0
Example A1-18 r Triazine derivative R Octylamine 1.0
Example A1-19 s Triazine derivative S Octylamine 1.0
Example A1-20 t Triazine derivative T Octylamine 1.0
Example A1-21 u Triazine derivative B Propylamine 1.0
Example A1-22 v Triazine derivative B Stearylamine 1.0
Example A1-23 w Triazine derivative B 2-Aminoethanol 1.0
Example A1-24 x Triazine derivative B Dibutylamine 1.0
Example A1-25 y Triazine derivative B Dioctylamine 1.0
Example A1-26 z Triazine derivative B Distearylamine 1.0
Example A1-27 aa Triazine derivative B Triethylamine 1.0
Example A1-28 ab Triazine derivative B Dimethyloctylamine 1.0
Example A1-29 ac Triazine derivative B Trioctylamine 1.0
Example A1-30 ad Triazine derivative B Dimethylstearylamine 1.0
Example A1-31 ae Triazine derivative B Triethanolamine 1.0
Example A1-32 af Triazine derivative B Octylamine 0.1
Example A1-33 ag Triazine derivative B Octylamine 0.3
Example A1-34 ah Triazine derivative B Octylamine 0.5
Example A1-35 ai Triazine derivative B Octylamine 2.0
Example A1-36 aj Triazine derivative B Octylamine 5.0
 

Example A1-1

      (Manufacture of Dispersant a)
      0.040 mol of the triazine derivative A was added to 200 g of water. 0.040 mol of octylamine was added thereto and stirred at 60° C. for 2 hours. After cooling to room temperature, filtration and purification were performed. The obtained residue was dried at 90° C. for 48 hours, and thereby a dispersant a was obtained.

[Example A1-2] to [Example A1-20]

      (Manufacture of Dispersant b to Dispersant t)
      A dispersant b to a dispersant t were obtained by manufacture in the same manner as in Example A1-1, except that a triazine derivative B to a triazine derivative T shown in Example A1-2 to Example A1-20 in Table 1 were added instead of the triazine derivative A in the manufacture of the dispersant a.

[Example A1-21] to [Example A1-31]

      (Manufacture of Dispersant u to Dispersant ae)
      A dispersant u to a dispersant ae were obtained by manufacture in the same manner as in Example A1-2 except that amines shown in Example A1-21 to Example A1-31 in Table 1 were added instead of octylamine in the manufacture of the dispersant b.

[Example A1-32] to [Example A1-36]

      (Manufacture of Dispersant af to Dispersant aj)
      A dispersant af to a dispersant aj were obtained by manufacture in the same manner as in Example A1-2 except that an amount of octylamine added in the manufacture of the dispersant b was changed to addition amounts which are shown in Example A1-32 to Example A1-36 in Table 1.
      Structures of triazine derivatives U to W used in comparative examples are shown below. A method for manufacturing the triazine derivatives U to W used in the comparative examples is not particularly limited, and a well-known method can be applied. For example, a method described in JP2004-217842A can be applied. The disclosure by the above publication is partially incorporated in the present specification by reference.

(MOL) (CDX)
      Dispersants ak to am shown in Table 2 were manufactured by methods described in the following comparative examples.
[TABLE-US-00002]
TABLE 2
 
        Molar equivalent
        of amine with
        respect to
    Triazine   triazine
  Dispersant derivative Amine derivative
 
Comparative ak Triazine Octylamine 1.0
Example A1-1   derivative U    
Comparative al Triazine Octylamine 1.0
Example A1-2   derivative V    
Comparative am Triazine Octylamine 1.0
Example A1-3   derivative W
 

[Comparative Example A1-1] to [Comparative Example A1-3]

      (Manufacture of Dispersant ak to Dispersant am)
      A dispersant ak to a dispersant am were obtained by manufacture in the same manner as in Example A1-1, except that the triazine derivative U to the triazine derivative W shown in Comparative Example A1-1 to Comparative Example A1-3 in Table 2 were added instead of the triazine derivative A in the manufacture of the dispersant a.

Example A2-1

      <Preparation of Carbon Material Dispersion Liquid>
      According to the composition shown in Table 3, N-methyl-2-pyrrolidone and the dispersant a were added to a glass bottle and mixed. Thereafter, a carbon material was added thereto and dispersed with a paint conditioner for 2 hours using zirconia beads as media. Thereby, a carbon material dispersion liquid containing the dispersant a was obtained.
      <Preparation of Carbon Material Dispersion Varnish>
      According to the composition shown in Table 4, the prepared seed carbon material dispersion liquid containing the dispersant a was mixed with a binder and N-methyl-2-pyrrolidone with a disper. Thereby, a carbon material dispersion varnish was obtained.
      <Preparation of Mixture Paste>
      According to the composition shown in Table 5, the prepared seed carbon material dispersion varnish containing the dispersant a was mixed with an active material and N-methyl-2-pyrrolidone with a disper. Thereby, a cathode mixture paste was obtained.
      <Production of Electrode>
      The prepared cathode mixture paste containing the dispersant a was applied onto an aluminum foil having a thickness of 20 μm using a doctor blade, and then dried at 120° C. for 30 minutes under reduced pressure. Thereafter, the aluminum foil was rolled with a roller pressing machine. Thereby, an electrode having an application amount of 17 mg/cm 2 and a density of 3.0 g/cm 3 was produced. An electrode having a uniform thickness and density was obtained.
      <Assembly of Cell for Evaluation Cathode of Lithium Ion Secondary Battery>
      The produced electrode containing the dispersant a was punched out to a diameter of 16 mm to be used as a cathode, and a metallic lithium foil (a thickness of 0.15 mm) was used as an anode. A separator made of a porous polypropylene film (a thickness of 20 μm, and a porosity of 50%) was inserted and laminated between the cathode and the anode, and was filled with 0.1 ml of an electrolyte solution (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate was mixed at a volume ratio of 1:1). Thereby, a closed bipolar metal cell (HS Flat Cell manufactured by Hohsen Corp.) was assembled. The cell was assembled in a glove box purged with argon gas.

[Examples A2-2 to A2-36] Comparison 1 of Dispersant Types

      A cell for cathode evaluation was assembled by dispersion in the same manner as in Example A2-1 except that the dispersants b to aj shown in Table 3 were used instead of the dispersant a.
      (Composition of Carbon Material Dispersion Liquid)
[TABLE-US-00003]
TABLE 3
 
  Composition of carbon material dispersion liquid
  Dispersant Carbon material Solvent
    Con-   Con-   Con-
    tent   tent   tent
  Type (%) Type (%) Type (%)
 
Example A2-1 a 0.2 HS100 10.0 NMP 89.8
Example A2-2 b 0.2 HS100 10.0 NMP 89.8
Example A2-3 c 0.2 HS100 10.0 NMP 89.8
Example A2-4 d 0.2 HS100 10.0 NMP 89.8
Example A2-5 e 0.2 HS100 10.0 NMP 89.8
Example A2-6 f 0.2 HS100 10.0 NMP 89.8
Example A2-7 g 0.2 HS100 10.0 NMP 89.8
Example A2-8 h 0.2 HS100 10.0 NMP 89.8
Example A2-9 i 0.2 HS100 10.0 NMP 89.8
Example A2-10 j 0.2 HS100 10.0 NMP 89.8
Example A2-11 k 0.2 HS100 10.0 NMP 89.8
Example A2-12 l 0.2 HS100 10.0 NMP 89.8
Example A2-13 m 0.2 HS100 10.0 NMP 89.8
Example A2-14 n 0.2 HS100 10.0 NMP 89.8
Example A2-15 o 0.2 HS100 10.0 NMP 89.8
Example A2-16 p 0.2 HS100 10.0 NMP 89.8
Example A2-17 q 0.2 HS100 10.0 NMP 89.8
Example A2-18 r 0.2 HS100 10.0 NMP 89.8
Example A2-19 s 0.2 HS100 10.0 NMP 89.8
Example A2-20 t 0.2 HS100 10.0 NMP 89.8
Example A2-21 u 0.2 HS100 10.0 NMP 89.8
Example A2-22 v 0.2 HS100 10.0 NMP 89.8
Example A2-23 w 0.2 HS100 10.0 NMP 89.8
Example A2-24 x 0.2 HS100 10.0 NMP 89.8
Example A2-25 y 0.2 HS100 10.0 NMP 89.8
Example A2-26 z 0.2 HS100 10.0 NMP 89.8
Example A2-27 aa 0.2 HS100 10.0 NMP 89.8
Example A2-28 ab 0.2 HS100 10.0 NMP 89.8
Example A2-29 ac 0.2 HS100 10.0 NMP 89.8
Example A2-30 ad 0.2 HS100 10.0 NMP 89.8
Example A2-31 ae 0.2 HS100 10.0 NMP 89.8
Example A2-32 af 0.2 HS100 10.0 NMP 89.8
Example A2-33 ag 0.2 HS100 10.0 NMP 89.8
Example A2-34 ah 0.2 HS100 10.0 NMP 89.8
Example A2-35 ai 0.2 HS100 10.0 NMP 89.8
Example A2-36 aj 0.2 HS100 10.0 NMP 89.8
 
[TABLE-US-00004]
TABLE 4
 
  Composition of carbon material dispersion varnish
    Carbon    
  Dispersant material Binder Solvent
    Con-   Con-   Con-   Con-
    tent   tent   tent   tent
  Type (%) Type (%) Type (%) Type (%)
 
Example A2-1 a 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-2 b 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-3 c 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-4 d 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-5 e 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-6 f 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-7 g 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-8 h 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-9 i 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-10 j 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-11 k 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-12 l 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-13 m 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-14 n 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-15 o 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-16 p 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-17 q 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-18 r 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-19 s 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-20 t 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-21 u 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-22 v 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-23 w 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-24 x 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-25 y 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-26 z 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-27 aa 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-28 ab 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-29 ac 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-30 ad 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-31 ae 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-32 af 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-33 ag 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-34 ah 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-35 ai 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-36 aj 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
 
      (Composition of Cathode Mixture Paste)
[TABLE-US-00005]
TABLE 5
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example A2-1 a 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-2 b 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-3 c 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-4 d 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-5 e 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-6 f 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-7 g 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-8 h 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-9 i 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-10 j 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-11 k 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-12 l 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-13 m 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-14 n 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-15 o 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-16 p 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-17 q 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-18 r 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-19 s 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-20 t 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-21 u 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-22 v 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-23 w 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-24 x 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-25 y 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-26 z 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-27 aa 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-28 ab 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-29 ac 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-30 ad 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-31 ae 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-32 af 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-33 ag 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-34 ah 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-35 ai 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-36 aj 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
 

[Comparative Examples A2-1 to A2-4] Comparison 2 of Dispersant Types

      According to materials and compositions of the carbon material dispersion liquids shown in Table 6, the carbon material dispersion varnishes shown in Table 7, and the cathode mixture pastes shown in Table 8, dispersion was performed in the same manner as in Example A2-1, and thereby a cell for cathode evaluation was assembled. In Comparative Example A2-4, a dispersant was not used.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00006]
TABLE 6
 
  Composition of carbon material dispersion liquid
      Carbon    
  Dispersant material Solvent
    Content   Content   Content
  Type (%) Type (%) Type (%)
 
Comparative ak 0.2 HS100 10.0 NMP 89.8
Example A2-1            
Comparative al 0.2 HS100 10.0 NMP 89.8
Example A2-2            
Comparative am 0.2 HS100 10.0 NMP 89.8
Example A2-3            
Comparative Not used 0 HS100 10.0 NMP 90.0
Example A2-4
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00007]
TABLE 7
 
  Composition of carbon material dispersion varnish
    Carbon    
  Dispersant material Binder Solvent
    Con-   Con-   Con-   Con-
    tent   tent   tent   tent
  Type (%) Type (%) Type (%) Type (%)
 
Comparative ak 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-1                
Comparative al 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-2                
Comparative am 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-3                
Comparative Not 0 HS100 6.0 PVDF 6.0 NMP 88.0
Example A2-4 used              
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00008]
TABLE 8
 
  Composition of cathode mixture paste
    Carbon      
  Dispersant material Binder Binder Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Comparative ak 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-1                    
Comparative al 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 44.0
Example A2-2                    
Comparative am 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 44.0
Example A2-3                    
Comparative Not 0 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-4 used
 
      <Evaluation of Ionic Resistance>
      The cell for cathode evaluation assembled in Examples A2-1 to A2-36 and Comparative Examples A2-1 to A2-4 was allowed to stand in a constant-temperature tank at −20° C. for 12 hours. An AC impedance was measured at an open circuit potential with a frequency of 0.1 Hz and an amplitude of 10 mV to obtain an ionic resistance |Z| ion. Subsequently, the cell for cathode evaluation was moved into room temperature (25° C.) and allowed to stand for 3 hours, and the impedance was measured in the same manner to obtain the ionic resistance |Z| ion. An impedance analyzer was used for the measurement.
      <Evaluation of Reaction Resistance>
      Following the evaluation of ionic resistance, using a charge and discharge measuring device, a total of 5 cycles were carried out, with one cycle being charging and discharging in which full charging was performed with 0.1C constant current-constant voltage charging (an upper limit voltage of 4.2V) at room temperature, and discharging was performed with a constant current of 0.1C to a discharge lower limit voltage of 3.0V. 0.1C discharge capacity at the fifth cycle was recorded. Next, the cell for cathode evaluation in a state of being discharged to 3.0V was connected to an impedance analyzer, and AC impedance measurement was performed at 3.0V, an amplitude of 10 mV, and a frequency from 0.1 Hz to 1 MHz. When the results were plotted on the complex plane by a Cole-Cole plot method, a semicircular curve was obtained. A size of an arc was defined as a reaction resistance |Z| re of the active material.
      <Evaluation of Room Temperature Rate Characteristic and Low-Temperature Discharge Characteristic>
      Next, after full charging with 0.1C at room temperature in the same manner, discharging was performed with a constant current of 0.5C to a discharge lower limit voltage of 3.0V, full charging was performed again with 0.1C, and then discharging was performed with a constant current of 5C to 3.0V. A ratio of 5C discharge capacity to 0.1C discharge capacity at the fifth cycle recorded in a test of reaction resistance evaluation was defined as a room temperature rate characteristic (%). In addition, a 0.5C discharge capacity at room temperature was recorded. Subsequently, full charging was performed with 0.1C at room temperature in the same manner. Thereafter, the battery was transferred to a −20° C. constant-temperature tank, left for 12 hours, and then discharged with a constant current of 0.5C. A ratio of 0.5C discharge capacity at −20° C. to 0.5C discharge capacity at room temperature was defined as a low-temperature discharge characteristic (%). As the room temperature rate characteristic and low-temperature discharge characteristic become closer to 100%, the characteristics become more favorable.
      <Evaluation Results>
      The carbon material dispersion liquids, carbon material dispersion varnishes, and cathode mixture pastes shown in Examples A2-1 to A2-36 and Comparative Examples A2-1, A2-2 were in a favorably dispersed state, and sedimentation or thickening did not occur even after the elapse of one month. The carbon material dispersion liquid, carbon material dispersion varnish, and cathode mixture paste of Comparative Example A2-3 had a high viscosity from the initial stage, and their dispersibility was considerably reduced. Regarding the carbon material dispersion liquid, carbon material dispersion varnish, and cathode mixture paste of Comparative Example A2-4 in which a dispersant was not used, a viscosity was considerably high and fluidity was inferior from the initial stage, but they were used as themselves for comparison. In addition, after the elapse of one month, the dispersed material had gelled.
      Table 9 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Examples A2-1 to A2-36 and Comparative Examples A2-1 to A2-4.
[TABLE-US-00009]
TABLE 9
 
            Low-
          Room temper-
          temper- ature
          ature dis-
    |Z|ion |Z|ion |Z|re rate charge
    at at at char- char-
  Dis- 25° −20° 25° acter- acter-
  persant C. C. C. istic istic
  Type [Ω] [Ω] [Ω] [%] [%]
 
 
Example A2-1 a 10 428 5.5 68.0 74.2
Example A2-2 b 10 420 5.0 68.8 75.2
Example A2-3 c 10 425 5.4 68.2 74.0
Example A2-4 d 14 487 8.1 62.4 63.2
Example A2-5 e 14 488 8.0 62.5 63.0
Example A2-6 f 12 477 6.9 64.4 70.0
Example A2-7 g 12 470 7.0 64.7 71.2
Example A2-8 h 11 447 6.7 66.0 72.0
Example A2-9 i 12 473 7.2 64.3 70.9
Example A2-10 j 11 451 6.6 65.7 72.4
Example A2-11 k 12 468 7.1 64.1 70.1
Example A2-12 l 12 479 7.3 64.2 70.4
Example A2-13 m 12 473 7.1 64.1 70.3
Example A2-14 n 11 440 6.4 65.3 72.0
Example A2-15 o 10 430 5.9 66.8 74.5
Example A2-16 p 14 490 7.7 63.1 63.0
Example A2-17 q 12 477 7.2 64.0 69.8
Example A2-18 r 12 475 7.4 64.5 70.0
Example A2-19 s 14 486 7.9 63.7 62.1
Example A2-20 t 14 492 7.8 63.5 62.5
Example A2-21 u 11 450 6.3 65.9 71.8
Example A2-22 v 10 431 5.7 66.7 74.2
Example A2-23 w 12 472 7.6 64.8 68.8
Example A2-24 x 12 474 7.5 64.1 70.0
Example A2-25 y 13 480 7.7 63.7 64.0
Example A2-26 z 14 483 7.9 63.0 61.2
Example A2-27 aa 11 435 6.4 65.7 72.0
Example A2-28 ab 10 428 5.7 67.1 74.3
Example A2-29 ac 14 481 7.8 62.8 62.0
Example A2-30 ad 11 446 6.2 65.8 72.8
Example A2-31 ae 12 477 7.3 64.0 68.0
Example A2-32 af 11 444 6.1 65.5 72.5
Example A2-33 ag 10 433 5.8 67.2 75.0
Example A2-34 ah 10 429 5.8 67.3 74.8
Example A2-35 ai 11 442 6.0 65.0 73.0
Example A2-36 aj 12 479 7.2 63.9 69.3
Comparative ak 18 650 10.0 52.9 48.0
Example A2-1            
Comparative al 17 644 9.8 54.1 49.0
Example A2-2            
Comparative am 16 601 9.1 56.8 52.8
Example A2-3            
Comparative Not 16 606 9.2 57.0 53.0
Example A2-4 used
 
      As can be seen from Table 9, the cathodes of Examples A2-1 to A2-36 in which the dispersants a to aj were used were extremely excellent in the all ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic at room temperature and −20° C., as compared to the cathodes of Comparative Example A2-4 in which a dispersant was not used, and Comparative Examples A2-1 to A2-3 in which the dispersants ak to am were used. The dispersants ak and al had particularly high ionic resistance at low temperatures and poor low-temperature discharge characteristic.
      The reason for this is thought to be that, because Li + with extremely high electron density is present near the dispersants a to aj, dielectric polarization occurs, and thereby the dispersants have a high dielectric constant in a battery. It is considered that, accordingly, ionic conductivity is improved, and desolvation energy and solvation energy of Li + when an active material reacts with Li are reduced. As a result, ionic resistance and reaction resistance are reduced, and therefore characteristics in terms of the whole battery is also improved.

[Examples A3-1 to A3-5] [Comparative Examples A3-1 to A3-5] Comparison of Carbon Material Types

      According to materials and compositions of the carbon material dispersion liquid shown in Table 10, the carbon material dispersion varnish shown in Table 11, and the cathode mixture paste shown in Table 12, dispersion was performed in the same manner as in Example A2-1, and thereby a cell for cathode evaluation was assembled. Because a large amount of dispersant is required for carbon materials with a high specific surface area, an appropriate amount to be used was determined according to each carbon material.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00010]
TABLE 10
 
  Composition of carbon material dispersion liquid
      Carbon    
  Dispersant material Solvent
    Con-   Con-   Con-
    tent   tent   tent
  Type (%) Type (%) Type (%)
 
Example A3-1 b 0.4 super-P 10.0 NMP 89.6
Example A3-2 b 0.4 M800 10.0 NMP 89.6
Example A3-3 b 1.0 EC-300J 10.0 NMP 89.0
Example A3-4 b 1.0 CNT 2.0 NMP 97.0
Example A3-5 b 0.2 VGCF 10.0 NMP 89.8
Comparative ak 0.4 super-P 10.0 NMP 89.6
Example A3-1            
Comparative ak 0.4 M800 10.0 NMP 89.6
Example A3-2            
Comparative ak 1.0 EC-300J 10.0 NMP 89.0
Example A3-3            
Comparative ak 1.5 CNT 3.0 NMP 95.5
Example A3-4            
Comparative ak 0.2 VGCF 10.0 NMP 89.8
Example A3-5
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00011]
TABLE 11
 
  Composition of carbon material dispersion varnish
    Carbon    
  Dispersant material Binder Solvent
    Con-   Con-   Con-   Con-
    tent   tent   tent   tent
  Type (%) Type (%) Type (%) Type (%)
 
Example A3-1 b 0.24 super-P 6.0 PVDF 6.0 NMP 87.8
Example A3-2 b 0.24 M800 6.0 PVDF 6.0 NMP 87.8
Example A3-3 b 0.6  EC-300J 6.0 PVDF 6.0 NMP 87.4
Example A3-4 b 1.45 CNT 2.9 PVDF 2.9 NMP 92.8
Example A3-5 b 0.12 VGCF 6.0 PVDF 6.0 NMP 87.9
Comparative ak 0.24 super-P 6.0 PVDF 6.0 NMP 87.8
Example A3-1                
Comparative ak 0.24 M800 6.0 PVDF 6.0 NMP 87.8
Example A3-2                
Comparative ak 0.6  EC-300J 6.0 PVDF 6.0 NMP 87.4
Example A3-3                
Comparative ak 1.45 CNT 2.9 PVDF 2.9 NMP 92.8
Example A3-4                
Comparative ak 0.12 VGCF 6.0 PVDF 6.0 NMP 87.9
Example A3-5
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00012]
TABLE 12
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example b 0.08 super-P 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
A3-1                    
Example b 0.08 M800 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
A3-2                    
Example b 0.2 EC-300J 2.0 PVDF 2.0 NMC 54.0 NMP 41.8
A3-3                    
Example b 0.390 CNT 1.3 PVDF 1.3 NMC 54.0 NMP 43.0
A3-4                    
Example b 0.04 VGCF 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
A3-5                    
Comparative ak 0.08 super-P 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example                    
A3-1                    
Comparative ak 0.08 M800 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example                    
A3-2                    
Comparative ak 0.2 EC-300J 2.0 PVDF 2.0 NMC 54.0 NMP 41.8
Example                    
A3-3                    
Comparative ak 0.390 CNT 1.3 PVDF 1.3 NMC 54.0 NMP 43.0
Example                    
A3-4                    
Comparative ak 0.04 VGCF 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example                    
A3-5
 
      <Evaluation Results>
      The carbon material dispersion liquids, carbon material dispersion varnishes, and cathode mixture pastes shown in all of the examples and comparative examples were also in a favorably dispersed state, and sedimentation or thickening did not occur even after the elapse of one month.
      Table 13 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Examples A3-1 to A3-5 and Comparative Examples A3-1 to A3-5.
[TABLE-US-00013]
TABLE 13
 
            Low-
          Room temper-
          temper- ature
          ature dis-
    |Z|ion |Z|ion |Z|re rate charge
    at at at char- char-
  Carbon 25° −20° 25° acter- acter-
  material C. C. C. istic istic
  Type [Ω] [Ω] [Ω] [%] [%]
 
 
Example A3-1 super-P 12 475 7.3 63.8 64.2
Example A3-2 M800 13 473 7.7 64.2 62.3
Example A3-3 EC-300J 10 420 5.9 65.7 72.8
Example A3-4 CNT 11 436 6.4 67.1 75.0
Example A3-5 VGCF 14 449 8.1 62.1 61.9
Comparative super-P 18 643 10.1 52.7 48.3
Example A3-1            
Comparative M800 18 640 9.7 53.2 48.4
Example A3-2            
Comparative EC-300J 20 661 10.1 52.3 48.0
Example A3-3            
Comparative CNT 21 669 10.3 51.9 47.7
Example A3-4            
Comparative VGCF 18 645 9.8 52.6 48.3
Example A3-5
 
      The same effects were confirmed for all the carbon materials. Differences between Examples A3-1 to A3-5 were thought to be differences due to conductivities of the carbon materials. In addition, in Comparative Examples A3-1 to A3-5, as an amount of dispersant added became larger, the low-temperature ionic resistance tended to become higher.
      Based on the above verification, it was confirmed that the above-described effects were not dependent on the type of carbon material.

[Examples A4-1 to A4-6] Comparison 1 of Amount of Dispersant Per Active Material Surface Area

      A cell for cathode evaluation was assembled in the same manner except that dispersant amounts shown in Table 14, Table 15, and Table 16 were used instead of the dispersant amount in Example A2-1. Table 17 shows a dispersant amount (mg) with respect to 1 m 2 active material surface area in the electrode.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00014]
TABLE 14
 
  Composition of carbon material dispersion liquid
    Carbon  
  Dispersant material Solvent
    Con-   Con-   Con-
    tent   tent   tent
  Type (%) Type (%) Type (%)
 
Comparative Not 0 HS100 10.0 NMP 90.0
Example A2-4 used          
Example A4-1 b 0.01 HS100 10.0 NMP 90.0
Example A4-2 b 0.02 HS100 10.0 NMP 90.0
Example A4-3 b 0.05 HS100 10.0 NMP 90.0
Example A4-4 b 0.1 HS100 10.0 NMP 89.9
Example A2-2 b 0.2 HS100 10.0 NMP 89.8
Example A4-5 b 0.4 HS100 10.0 NMP 89.6
Example A4-6 b 0.8 HS100 10.0 NMP 89.2
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00015]
TABLE 16
 
  Composition of carbon material dispersion varnish
    Carbon    
  Dispersant material Binder Solvent
    Con-   Con-   Con-   Con-
    tent   tent   tent   tent
  Type (%) Type (%) Type (%) Type (%)
 
Comparative Not 0 HS100 6.0 PVDF 6.0 NMP 88.0
Example A2-4 used              
Example A4-1 b 0.006 HS100 6.0 PVDF 6.0 NMP 88.0
Example A4-2 b 0.012 HS100 6.0 PVDF 6.0 NMP 88.0
Example A4-3 b 0.03 HS100 6.0 PVDF 6.0 NMP 88.0
Example A4-4 b 0.06 HS100 6.0 PVDF 6.0 NMP 87.9
Example A2-2 b 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example A4-5 b 0.24 HS100 6.0 PVDF 6.0 NMP 87.8
Example A4-6 b 0.48 HS100 6.0 PVDF 6.0 NMP 87.5
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00016]
TABLE 16
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Comparative Not 0 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-4 used                  
Example A4-1 b 0.002 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A4-2 b 0.004 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A4-3 b 0.01 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A4-4 b 0.02 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A2-2 b 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example A4-5 b 0.08 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example A4-6 b 0.16 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 41.8
 
      (Amount of Dispersant Per Active Material Surface Area)
[TABLE-US-00017]
  TABLE 17
   
    Dispersant amount per active
    material surface area (mg/m2)
   
 
  Comparative 0
  Example A2-4  
  Example A4-1 0.06
  Example A4-2 0.12
  Example A4-3 0.30
  Example A4-4 0.60
  Example A2-2 1.19
  Example A4-5 2.39
  Example A4-6 4.78
   
      <Evaluation Results>
      Table 18 shows evaluation results of reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Comparative Example A2-4, Example A2-2, and Examples A4-1 to A4-6.
[TABLE-US-00018]
TABLE 18
 
  Dispersant   Room Low-
  amount per   temperature temperature
  active material |Z|re at rate discharge
  surface area 25° C. characteristic characteristic
  (mg/m2) [Ω] [%] [%]
 
 
Comparative 0 9.2 57.0 53.0
Example A2-4        
Example A4-1 0.06 8.0 62.6 63.1
Example A4-2 0.12 6.9 65.2 71.1
Example A4-3 0.30 6.8 65.4 70.9
Example A4-4 0.60 6.3 66.6 72.1
Example A2-2 1.19 5.0 68.8 75.2
Example A4-5 2.39 5.1 69.2 75.5
Example A4-6 4.78 5.1 69.7 75.9
 
      Based on Example A4-1, it was found that when a dispersant amount with respect to the active material surface area was too small, the effects were diminished. An excellent effect was obtained when a dispersant amount became larger than that of Example A4-2, and the effect was gradually improved as the dispersant amount increased.

[Examples A5-1 to A5-8] Comparison 2 of Amount of Dispersant Per Active Material Surface Area

      Dispersion was performed in the same manner as in Example A2-1 with materials and compositions shown in Table 19, Table 20, and Table 21, and thereby a cell for cathode evaluation was produced. Table 22 shows a dispersant amount (mg) with respect to 1 m 2 active material surface area in the electrode.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00019]
TABLE 19
 
  Composition of carbon material dispersion liquid
  Dispersant Carbon material Solvent
    Content   Content   Content
  Type (%) Type (%) Type (%)
 
Example A5-1 b  1.98 CNT 6.6 NMP 91.4
Example A5-2 b 3.3 CNT 6.6 NMP 90.1
Example A5-3 b 6.6 CNT 6.6 NMP 86.8
Example A5-4 b 9.9 CNT 6.6 NMP 83.5
Example A5-5 b 11.6  CNT 6.6 NMP 81.9
Example A5-6 b 13.2  CNT 6.6 NMP 80.2
Example A5-7 b 14.9  CNT 6.6 NMP 78.6
Example A5-8 b 16.5  CNT 6.6 NMP 76.9
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00020]
TABLE 20
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder Solvent
    Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%)
 
Example b  1.86 CNT 6.2 PVDF 5.0 NMP 86.9
A5-1                
Example b 3.1 CNT 6.2 PVDF 5.0 NMP 85.7
A5-2                
Example b 6.2 CNT 6.2 PVDF 5.0 NMP 82.6
A5-3                
Example b 9.3 CNT 6.2 PVDF 5.0 NMP 79.5
A5-4                
Example b 10.9  CNT 6.2 PVDF 5.0 NMP 78.0
A5-5                
Example b 12.4  CNT 6.2 PVDF 5.0 NMP 76.4
A5-6                
Example b 14.0  CNT 6.2 PVDF 5.0 NMP 74.9
A5-7                
Example b 15.5  CNT 6.2 PVDF 5.0 NMP 73.3
A5-8
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00021]
TABLE 21
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example b  0.93 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 43.5
A5-1                    
Example b 1.6 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 42.9
A5-2                    
Example b 3.1 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 41.3
A5-3                    
Example b 4.7 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 39.8
A5-4                    
Example b 5.4 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 39.0
A5-5                    
Example b 6.2 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 38.2
A5-6                    
Example b 7.0 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 37.4
A5-7                    
Example b 7.8 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 36.7
A5-8
 
      (Amount of Dispersant Per Active Material Surface Area)
[TABLE-US-00022]
  TABLE 22
   
    Dispersant amount per active
    material surface area
    (mg/m2)
   
 
  Example A5-1 30
  Example A5-2 50
  Example A5-3 100
  Example A5-4 150
  Example A5-5 175
  Example A5-6 200
  Example A5-7 225
  Example A5-8 250
   
      <Evaluation Results>
      Table 23 shows evaluation results of reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example A5-1 to Example A5-8.
[TABLE-US-00023]
TABLE 23
 
  Dispersant   Room Low-
  amount per   temperature temperature
  active material |Z|re at rate discharge
  surface area 25° C. characteristic characteristic
  (mg/m2) [Ω] [%] [%]
 
 
Example A5-1 30 5.6 66.7 72.8
Example A5-2 50 5.6 68.1 74.1
Example A5-3 100 5.6 69.2 74.3
Example A5-4 150 5.6 67.6 73.9
Example A5-5 175 6.4 66.3 70.1
Example A5-6 200 7.4 64.6 69.7
Example A5-7 225 8.0 63.8 62.6
Example A5-8 250 8.1 63.3 62.1
 
      Based on Table 23, it was found that when a dispersant amount exceeded the dispersant amount in Example A5-6, an effect of reducing reaction resistance was diminished. The reason for this was thought to be that, when a dispersant amount was in excess, the adverse effect of a resistance component becoming larger than an amount of reduction in desolvation energy.
      Based on the above results, it was found that there is an optimum range for an amount of dispersant added to the active material surface area for obtaining an excellent effect of reducing reaction resistance.

[Examples A6-1 to A6-6] Comparison 1 of Amount of Dispersant with Respect to Amount of Electrolyte Solution

      A cell for cathode evaluation was assembled in the same manner as in Example A4-2, except that an amount of an electrolyte solution was changed to an amount shown in Table 24 using the cathode produced in Example A4-2.
[TABLE-US-00024]
TABLE 24
 
  Electrolyte Dispersant amount with
  solution amount respect to electrolyte
  added in cell solution amount
  (ml) (mg/ml)
 
 
Example A6-1 0.05 0.12
Example A4-2 0.1 0.059
Example A6-2 0.2 0.023
Example A6-3 0.4 0.015
Example A6-4 0.6 0.010
Example A6-5 0.7 0.007
Example A6-6 1.2 0.005
 

[Examples A7-1 to A7-7] Comparison 2 of Amount of Dispersant with Respect to Amount of Electrolyte Solution

      A cathode was produced in the same manner as in Example A5-3 except that the cathode mixture paste produced in Example A5-3 was used, and a coating amount was changed to 28 mg/cm 2. In addition, a cell for cathode evaluation was assembled in the same manner as in Example A5-3 except that an amount of electrolyte solution added to the cell for cathode evaluation was changed to an amount shown in Table 25.
[TABLE-US-00025]
TABLE 25
 
  Electrolyte solution Dispersant amount with respect
  amount added in cell to electrolyte solution amount
  (ml) (mg/ml)
 
 
Example A7-1 0.03 99.1
Example A7-2 0.04 74.3
Example A7-3 0.05 59.4
Example A7-4 0.06 49.3
Example A7-5 0.08 37.2
Example A7-6 0.1 29.7
Example A7-7 0.2 14.9
 
      <Evaluation Results>
      Table 26 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example A4-2, Examples A6-1 to A6-6, and Comparative Example A2-4. Table 27 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example A7-1 to Example A7-7.
      The reaction resistances of Example A4-2 and Examples A6-1 to A6-6 were all the same level. The reason for this is thought to be that amounts of dispersant with respect to the active material surface area were the same.
      In addition, the ionic resistance at room temperature and low temperature was low in Examples A6-1 to A6-4, and the effects were poor in Examples A6-5 and A6-6 with Example A6-4 as the lower limit. It was shown that there is a lower limit of an optimum amount of dispersant with respect to an amount of electrolyte solution for obtaining an excellent effect.
      Because room temperature rate characteristic and low-temperature discharge characteristic are affected by both ionic resistance and reaction resistance, there is a need for a design in which both effects can be obtained, in order to obtain excellent characteristics in a battery.
      Meanwhile, from the comparison between Examples A7-1 to A7-7, it was found that the effect of reducing ionic resistance was diminished even when an amount of dispersant is too large with respect to an amount of electrolyte solution. The reason for this is thought to be that because the dispersant is an insulating compound, when an amount thereof is in excess, the dispersant becomes a resistance component itself.
      Based on the above results, it was found that there is also an upper limit to an optimum amount of dispersant with respect to an amount of electrolyte solution.
[TABLE-US-00026]
TABLE 26
 
  Dispersant          
  amount with       Room Low-
  respect to       temperature temperature
  electrolyte |Z|ion at Z|ion at |Z|re at rate discharge
  solution amount 25° C. −20° C. 25° C. characteristic characteristic
  (mg/ml) [Ω] [Ω] [Ω] [%] [%]
 
 
Example A6-1 0.12 10 429 6.6 68.1 74.2
Example A4-2 0.059 10 450 6.8 65.2 71.1
Example A6-2 0.023 11 478 6.9 64.5 71.9
Example A6-3 0.015 12 475 6.7 64.8 69.4
Example A6-4 0.010 12 477 6.7 64.1 69.1
Example A6-5 0.007 14 498 6.8 63.2 61.3
Example A6-6 0.005 14 503 6.8 62.9 61.8
Comparative 0 16 606 9.2 57.0 53.0
Example A2-4
 
[TABLE-US-00027]
 
  Dispersant          
  amount with       Room Low-
  respect to       temperature temperature
  electrolyte |Z|ion at Z|ion at |Z|re at rate discharge
  solution amount 25° C. −20° C. 25° C. characteristic characteristic
  (mg/ml) [Ω] [Ω] [Ω] [%] [%]
 
Example A7-1 99.1 14 521 5.7 61.9 60.6
Example A7-2 74.3 14 517 5.8 62.4 61.5
Example A7-3 59.4 10 422 5.6 67.1 74.8
Example A7-4 49.3 10 430 5.7 66.7 74.3
Example A7-5 37.2 10 448 5.7 66.2 73.9
Example A7-6 29.7 11 470 5.6 65.3 72.5
Example A7-7 14.9 12 482 5.7 64.9 71.8
 

[Example A8-1] Investigation of Influence of Electrolyte Solution

      A cell for cathode evaluation was assembled in the same manner as in Example A2-2 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:2, was used instead of the electrolyte solution used in Example A2-2 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).

Example A8-2

      A cell for cathode evaluation was assembled in the same manner as in Example A2-2 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate were mixed at a volume ratio of 1:1:1, was used instead of the electrolyte solution used in Example A2-2 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).
      A cell for cathode evaluation was assembled in the same manner as in Comparative Example A2-4 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:2, was used instead of the electrolyte solution used in Comparative Example A2-4 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).

Comparative Example A8-2

      A cell for cathode evaluation was assembled in the same manner as in Comparative Example A2-4 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate were mixed at a volume ratio of 1:1:1, was used instead of the electrolyte solution used in Comparative Example A2-4 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).
      <Evaluation Results>
      Table 28 shows evaluation results of ionic resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example A2-2, Example A8-1, Example A8-2, Comparative Example A2-4, Comparative Example A8-1, and Comparative Example A8-2.
[TABLE-US-00028]
TABLE 28
 
        Room Low-
        temperature temperature
  |Z|ion at |Z|ion at |Z|re at rate discharge
  25° C. −20° C. 25° C. characteristic characteristic
  [Ω] [Ω] [Ω] [%] [%]
 
 
Example A2-2 10 420 5.0 68.8 75.2
Example A8-1 9 413 5.1 69.2 76.6
Example A8-2 9 409 5.0 69.2 77.8
Comparative 16 606 9.1 57.0 53.0
Example A2-4          
Comparative 16 595 9.1 57.1 55.1
Example A8-1          
Comparative 16 592 9.2 57.2 55.4
Example A8-2          
 
      From Example A8-1 and Example A8-2, it was confirmed that all characteristics were improved regardless of the type of electrolyte solution. In addition to the electrolyte solutions shown in the present examples, the same effects are expected to be obtained regardless of the type of non-aqueous electrolyte solution as long as it is a non-aqueous electrolyte solution that is generally used.
      Next, the type of active material was changed, and evaluation was performed in the same manner.

[Examples A9-1 to A9-3] Comparison of Active Material Species

      Using the carbon material dispersion varnish used in Example A2-2, the cell for cathode evaluation was assembled by dispersion performed in the same manner as in Example A2-2 according to the active material and composition shown in Table 29.

Comparative Examples A9-1 to A9-3

      Using the carbon material dispersion varnish used in Comparative Example A2-1, the cell for cathode evaluation was assembled by dispersion performed in the same manner as in Comparative Example A2-1 according to the active material and composition shown in Table 30.
[TABLE-US-00029]
TABLE 29
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example A9-1 b 0.04 HS100 2.0 PVDF 2.0 LCO 54.0 NMP 42.0
Example A9-2 b 0.04 HS100 2.0 PVDF 2.0 NCA 54.0 NMP 42.0
Example A9-3 b 0.04 HS100 2.0 PVDF 2.0 LFP 48.0 NMP 48.0
 
[TABLE-US-00030]
TABLE 30
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Comparative ak 0.04 HS100 2.0 PVDF 2.0 LCO 54.0 NMP 42.0
Example A9-1                    
Comparative ak 0.04 HS100 2.0 PVDF 2.0 NCA 54.0 NMP 42.0
Example A9-2                    
Comparative ak 0.04 HS100 2.0 PVDF 2.0 LFP 48.0 NMP 48.0
Example A9-3
 
      <Evaluation Results>
      Table 31 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Examples A9-1 to A9-3 and Comparative Examples A9-1 to A9-3.
[TABLE-US-00031]
 
          Room Low-temperature
          temperature rate discharge
  Dispersant |Z|ion at Z|ion at |Z|re at characteristic characteristic
  Type 25° C. [Ω] −20° C. [Ω] 25° C. [Ω] [%] [%]
 
Example A9-1 b 10 425 5.0 68.4 75.1
Example A9-2 b 10 420 5.0 68.8 76.9
Example A9-3 b 10 418 6.3 72.2 80.4
Comparative ak 18 650 10.0  52.9 48.0
Example A9-1            
Comparative ak 18 637 10.0  53.1 52.7
Example A9-2            
Comparative ak 18 645 11.9  53.8 60.1
Example A9-3
 
      Although there were differences in battery characteristics depending on a performance of the active material, it was confirmed that all characteristics were improved when compared with those of the same active material.
      Subsequently, a case of use in the anode was evaluated.

Example A10-1

      <Preparation of Carbon Material Dispersion Varnish>
      According to the composition shown in Table 32, the carbon material dispersion liquid which contains the dispersant a and was produced in Example A2-1 was mixed with a binder and N-methyl-2-pyrrolidone with a disper. Thereby, a carbon material dispersion varnish was obtained.
      <Preparation of Mixture Paste>
      According to the composition shown in Table 33, the prepared seed carbon material dispersion varnish containing the dispersant a was mixed with an active material and N-methyl-2-pyrrolidone with a disper. Thereby, an anode mixture paste was obtained.
      <Production of Electrode>
      The prepared anode mixture paste containing the dispersant a was applied onto a copper foil having a thickness of 20 μm using a doctor blade, and then dried at 120° C. for 30 minutes under reduced pressure. Thereafter, the copper foil was rolled with a roller pressing machine. Thereby, an electrode having an application amount of 15 mg/cm 2 and a density of 1.8 g/cm 3 was produced. An electrode having a uniform thickness and density was obtained.
      <Assembly of Cell for Evaluation Anode of Lithium Ion Secondary Battery>
      The produced electrode containing the dispersant a was punched out to a diameter of 18 mm to be used as an anode, and a metallic lithium foil (a thickness of 0.15 mm) was used as a cathode. A separator made of a porous polypropylene film (a thickness of 20 μm, and a porosity of 50%) was inserted and laminated between the anode and the cathode, and was filled with 0.1 ml of an electrolyte solution (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate was mixed at a volume ratio of 1:1). Thereby, a closed bipolar metal cell (HS Flat Cell manufactured by Hohsen Corp.) was assembled. The cell was assembled in a glove box purged with argon gas.

Examples A10-2 to A10-36

      Using the carbon material dispersion liquids which respectively contain the dispersant b to the dispersant aj and were produced in Examples A2-2 to A2-36, a cell for anode evaluation was assembled by dispersion performed in the same manner as in Example A10-1 according to the materials and compositions shown in Table 32 and Table 33.
[TABLE-US-00032]
TABLE 32
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder Solvent
    Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%)
 
Example A10-1 a 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-2 b 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-3 c 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-4 d 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-5 e 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-6 f 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-7 g 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-8 h 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-9 i 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-10 j 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-11 k 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-12 1 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-13 m 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-14 n 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-15 o 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-16 p 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-17 q 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-18 r 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-19 s 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-20 t 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-21 u 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-22 v 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-23 w 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-24 x 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-25 y 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-26 z 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-27 aa 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-28 ab 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-29 ac 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-30 ad 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-31 ae 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-32 af 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-33 ag 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-34 ah 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-35 ai 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-36 aj 0.08 HS100 4.0 PVDF 8.0 NMP 87.9
 
[TABLE-US-00033]
TABLE 33
 
  Composition of anode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) (%) Type (%) Type (%) Type
 
Example A10-1 a 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-2 b 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP  50.47
              graphite      
Example A10-3 c 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-4 d 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-5 e 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-6 f 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-7 g 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-8 h 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-9 i 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-10 j 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-11 k 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-12 1 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-13 m 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-14 n 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-15 o 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-16 p 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-17 q 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-18 r 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-19 s 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-20 t 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-21 u 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-22 v 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-23 w 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-24 x 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-25 y 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-26 z 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-27 aa 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-28 ab 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-29 ac 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-30 ad 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-31 ae 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-32 af 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-33 ag 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-34 ah 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-35 ai 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite      
Example A10-36 aj 0.03 HS 100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
              graphite
 

Comparative Examples A10-1 to A10-4

      Using the carbon material dispersion liquids produced in Comparative Examples A2-1 to A2-4, a cell for anode evaluation was assembled by dispersing the carbon material dispersion varnish and the anode mixture paste in the same manner as in Example A10-1 according to the materials and compositions shown in Table 34 and Table 35. In Comparative Example A10-4, a dispersant was not used.
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00034]
TABLE 34
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder Solvent
    Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%)
 
Comparative ak   0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-1                
Comparative al   0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-2                
Comparative am   0.08 HS100 4.0 PVDF 8.0 NMP 87.9
Example A10-3                
Comparative Not used 0 HS100 4.0 PVDF 8.0 NMP 88.0
Example A10-4
 
      (Composition of Anode Mixture Pastes)
[TABLE-US-00035]
TABLE 35
 
  Composition of anode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Comparative ak   0.03 HS100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
Example A10-1             graphite      
Comparative al   0.03 HS100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
Example A10-2             graphite      
Comparative am   0.03 HS100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
Example A10-3             graphite      
Comparative Not 0 HS100 1.5 PVDF 3.0 Spheroidal 45.0 NMP 50.5
Example A10-4 used           graphite
 
      <Evaluation of Ionic Resistance>
      Impedance was measured under the same conditions as in Example A2-1, and the ionic resistance |Z| ion at −20° C. and room temperature (25° C.) was obtained.
      <Evaluation of Reaction Resistance>
      Following the evaluation of ionic resistance, using a charge and discharge measuring device, a total of 5 cycles were carried out, with one cycle being charging and discharging in which full charging was performed with 0.1C constant current-constant voltage charging (an upper limit voltage of 2.0V) at room temperature, and discharging was performed with a constant current of 0.1C to a discharge lower limit voltage of 0.0V. 0.1C discharge capacity at the fifth cycle was recorded. Next, the cell for anode evaluation in a state of being discharged to 0.0V was connected to an impedance analyzer, and AC impedance measurement was performed at 0.0V, an amplitude of 10 mV, and a frequency from 0.1 Hz to 1 MHz. When the results were plotted on the complex plane by a Cole-Cole plot method, a semicircular curve was obtained. A size of an arc was defined as a reaction resistance |Z| re of the active material.
      <Evaluation of Room Temperature Rate Characteristic and Low-Temperature Discharge Characteristic>
      Next, after full charging with 0.1C at room temperature, discharging was performed with a constant current of 0.5C to a discharge lower limit voltage of 0.0V, full charging was performed again with 0.1C, and then discharging was performed with a constant current of 5C to 0.0V. A ratio of a 5C discharge capacity to a 0.1C discharge capacity at the fifth cycle recorded in a test of reaction resistance evaluation was defined as a room temperature rate characteristic (%). In addition, a 0.5C discharge capacity at room temperature was recorded. Subsequently, full charging was performed with 0.1C at room temperature in the same manner. Thereafter, the battery was transferred to a −20° C. constant-temperature tank, left for 12 hours, and discharged with a constant current of 0.5C. A ratio of 0.5C discharge capacity at −20° C. to 0.5C discharge capacity at room temperature was defined as a low-temperature discharge characteristic (%).
      <Evaluation Results>
      The carbon material dispersion liquids, carbon material dispersion varnishes, and anode mixture pastes shown in Examples A10-1 to A10-36 and Comparative Examples A10-1 to A10-2 were in a favorably dispersed state, and sedimentation or thickening did not occur even after the elapse of one month. The carbon material dispersion liquid, carbon material dispersion varnish, and anode mixture paste of Comparative Example A10-3 had a high viscosity from the initial stage, and their dispersibility was considerably reduced. Regarding the carbon material dispersion liquid, carbon material dispersion varnish, and anode mixture paste of Comparative Example A10-4 in which a dispersant was not used, a viscosity was high and fluidity was inferior from the initial stage, but they were used as is for comparison. In addition, sedimentation of the active material was confirmed after the elapse of one month.
      Table 36 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Examples A10-1 to A10-36 and Comparative Examples A10-1 to A10-4.
[TABLE-US-00036]
TABLE 36
 
          Room  
          temperature  
    |Z|ion at |Z|ion at |Z|re at rate Low-temperature
  Dispersant 25° C. −20° C. 25° C. characteristic discharge
  Type [Ω] [Ω] [Ω] [%] characteristic [%]
 
Example A10-1 a 13 460 4.5 64.5 73.8
Example A10-2 b 13 452 4.3 65.5 76.0
Example A10-3 c 13 458 4.6 63.8 75.1
Example A10-4 d 20 604 6.6 59.3 61.4
Example A10-5 e 20 606 6.8 59.1 60.8
Example A10-6 f 18 580 5.9 60.0 71.0
Example A10-7 g 18 584 5.9 61.4 72.1
Example A10-8 h 16 520 5.7 62.8 70.8
Example A10-9 i 18 593 6.1 61.0 70.4
Example A10-10 j 16 520 5.5 62.6 72.0
Example A10-11 k 18 591 6.0 61.1 69.5
Example A10-12 l 18 587 6.2 60.8 69.9
Example A10-13 m 18 590 6.1 60.7 70.5
Example A10-14 n 16 550 5.4 62.5 71.7
Example A10-15 o 14 466 5.1 63.4 74.0
Example A10-16 p 20 600 6.5 59.9 62.4
Example A10-17 q 18 579 6.1 60.8 68.1
Example A10-18 r 18 577 6.2 61.3 71.1
Example A10-19 s 20 605 6.8 60.6 63.2
Example A10-20 t 20 603 6.7 60.4 63.5
Example A10-21 u 16 540 5.3 62.8 72.0
Example A10-22 v 14 467 4.8 63.8 73.8
Example A10-23 w 17 560 6.5 62.0 68.2
Example A10-24 x 17 565 6.4 60.7 71.0
Example A10-25 y 19 590 6.4 60.5 62.7
Example A10-26 z 20 608 6.7 59.7 63.4
Example A10-27 aa 15 530 5.4 62.4 72.9
Example A10-28 ab 13 461 4.8 63.7 73.1
Example A10-29 ac 20 607 6.7 59.5 64.5
Example A10-30 ad 16 540 5.3 62.1 73.4
Example A10-31 ae 18 592 6.2 60.7 67.5
Example A10-32 af 15 520 5.1 62.5 70.9
Example A10-33 ag 13 460 4.9 63.9 76.5
Example A10-34 ah 14 468 5.0 63.4 75.2
Example A10-35 ai 15 515 5.1 61.6 72.1
Example A10-36 aj 18 591 6.2 60.7 70.0
Comparative ak 25 730 8.5 50.2 47.0
Example A10-1            
Comparative al 25 722 8.3 51.1 48.0
Example A10-2            
Comparative am 23 694 7.7 53.4 52.3
Example A10-3            
Comparative Not used 23 693 7.8 54.1 52.8
Example A10-4
 
      The effect of reducing ionic resistance and reaction resistance was obtained also in the case of using the dispersion composition of the present invention for the anode, as in the case of using the dispersion composition of the present invention for the cathode.
      Dispersant aqueous solutions wa to xe shown in Table 37 were manufactured by methods described in the following examples.

Example A11-1

      (Manufacture of Dispersant Aqueous Solution wa)
      0.040 mol of the triazine derivative A was added to 200 g of water. 0.040 mol of sodium hydroxide was added thereto and stirred at 60° C. for 2 hours. After cooling to room temperature, a dispersant aqueous solution wa containing the triazine derivative A and the sodium hydroxide was obtained.

Example A11-2 to A11-20

      (Manufacture of Dispersant Aqueous Solutions wb to wt)
      Dispersant aqueous solutions wb to wt were obtained by manufacture in the same manner as in Example A11-1, except that a triazine derivative B to a triazine derivative T shown in Example A11-2 to Example A11-20 in Table 37 were added instead of the triazine derivative A in the manufacture of the dispersant wa.

Examples A11-21 to A11-26

      (Manufacture of Dispersant Aqueous Solutions wu to wz)
      Dispersant aqueous solutions wu to wz were obtained by manufacture in the same manner as in Example A11-2 except that each inorganic base shown in Table 37 was added instead of the sodium hydroxide in the manufacture of the dispersant aqueous solution wb.

Examples A11-27 to A11-31

      (Manufacture of Dispersant Aqueous Solutions xa to xe)
      Dispersant aqueous solutions xa to xe were obtained by manufacture in the same manner as in Example A11-2 except that an amount of sodium hydroxide added in the manufacture of the dispersant aqueous solution wb was changed to addition amounts which are shown in Examples A11-27 to A11-31 in Table 37.
[TABLE-US-00037]
TABLE 37
 
        Molar
        equivalent
        of inorganic
        base with
        respect to
  Disper-   Inorganic triazine
  sant Triazine derivative base derivative
 
Example A11-1 wa Triazine derivative A NaOH 1.0
Example A11-2 wb Triazine derivative B NaOH 1.0
Example A11-3 wc Triazine derivative C NaOH 1.0
Example A11-4 wd Triazine derivative D NaOH 1.0
Example A11-5 we Triazine derivative E NaOH 1.0
Example A11-6 wf Triazine derivative F NaOH 1.0
Example A11-7 wg Triazine derivative G NaOH 1.0
Example A11-8 wh Triazine derivative H NaOH 1.0
Example A11-9 wi Triazine derivative I NaOH 1.0
Example A11-10 wj Triazine derivative J NaOH 1.0
Example A11-11 wk Triazine derivative K NaOH 1.0
Example A11-12 wl Triazine derivative L NaOH 1.0
Example A11-13 wm Triazine derivative M NaOH 1.0
Example A11-14 wn Triazine derivative N NaOH 1.0
Example A11-15 wo Triazine derivative O NaOH 1.0
Example A11-16 wp Triazine derivative P NaOH 1.0
Example A11-17 wq Triazine derivative Q NaOH 1.0
Example A11-18 wr Triazine derivative R NaOH 1.0
Example A11-19 ws Triazine derivative S NaOH 1.0
Example A11-20 wt Triazine derivative T NaOH 1.0
Example A11-21 wu Triazine derivative B NaOH 1.0
Example A11-22 wv Triazine derivative B NaOH 1.0
Example A11-23 ww Triazine derivative B NaOH 1.0
Example A11-24 wx Triazine derivative B NaOH 1.0
Example A11-25 wy Triazine derivative B NaOH 1.0
Example A11-26 wz Triazine derivative B NaOH 1.0
Example A11-27 xa Triazine derivative B NaOH 0.1
Example A11-28 xb Triazine derivative B NaOH 0.3
Example A11-29 xc Triazine derivative B NaOH 0.5
Example A11-30 xd Triazine derivative B NaOH 2.0
Example A11-31 xe Triazine derivative B NaOH 5.0
 
      Dispersants xf to xh shown in Table 38 were manufactured by methods described in the following comparative examples.

Comparative Examples A11-1 to A11-3

      (Manufacture of Dispersants xf to xh)
      Dispersants xf to xh were obtained by manufacture in the same manner as in Example A11-1, except that the triazine derivative U to the triazine derivative W shown in Comparative Example A11-1 to Comparative Example A11-3 in Table 38 were added instead of the triazine derivative A in the manufacture of the dispersant wa.
[TABLE-US-00038]
TABLE 38
 
        Molar
        equivalent
        of inorganic
        base with
        respect to
      Inorganic triazine
  Dispersant Triazine derivative base derivative
 
Comparative xf Triazine derivative NaOH 1.0
Example A11-1   U    
Comparative xg Triazine derivative NaOH 1.0
Example A11-2   V    
Comparative xh Triazine derivative NaOH 1.0
Example A11-3   W
 

Example A12-1

      <Preparation of Carbon Material Dispersion Liquid>
      According to the composition shown in Table 39, water and the dispersant aqueous solution wa were added to a glass bottle and mixed. Thereafter, a carbon material was added thereto and dispersed with a paint conditioner for 2 hours using zirconia beads as media. Thereby, a carbon material dispersion liquid was obtained. At this time, an amount of dispersant aqueous solution added was determined with a total amount of triazine derivative A and NaOH as the active ingredient, such that a proportion of the active ingredient in a total amount of carbon material dispersion liquid was as in the composition shown in Table 39. In addition, water contained in the dispersant aqueous solution was used as the solvent for the carbon material dispersion liquid as it was, with more being added to make up any shortage.
      <Preparation of Carbon Material Dispersion Varnish>
      According to the composition shown in Table 40, the prepared carbon material dispersion liquid, a binder, and water were mixed with a disper. Thereby, a carbon material dispersion varnish was obtained.
      <Preparation of Mixture Paste>
      According to the composition shown in Table 41, the prepared carbon material dispersion varnish, an active material, and water were mixed with a disper. Thereby, a cathode mixture paste was obtained.
      <Production of Electrode>
      <Assembly of Cell for Evaluation Cathode of Lithium Ion Secondary Battery>
      A cell for cathode evaluation was assembled by producing an electrode in the same manner as in Example A2-1 except that the cathode mixture paste containing the dispersant aqueous solution wa was used instead of the cathode mixture paste containing the dispersant a in Example A2-1.

Examples A12-2 to A12-31

      A cell for cathode evaluation was assembled by dispersion in the same manner as in Example A12-1 except that the dispersants wb to xe shown in Table 39 were used instead of the dispersant wa.
[TABLE-US-00039]
TABLE 39
 
  Composition of carbon material dispersion liquid
  Dispersant aqueous      
  solution      
    Content of     Solvent Content
    active Carbon material   (%) containing
  Type ingredient (%) Type Content (%) Type dispersant aqueous
 
Example A12-1 wa 1.0 HS100 10.0 Water 89.0
Example A12-2 wb 1.0 HS100 10.0 Water 89.0
Example A12-3 wc 1.0 HS100 10.0 Water 89.0
Example A12-4 wd 1.0 HS100 10.0 Water 89.0
Example A12-5 we 1.0 HS100 10.0 Water 89.0
Example A12-6 wf 1.0 HS100 10.0 Water 89.0
Example A12-7 wg 1.0 HS100 10.0 Water 89.0
Example A12-8 wh 1.0 HS100 10.0 Water 89.0
Example A12-9 wi 1.0 HS100 10.0 Water 89.0
Example A12-10 wj 1.0 HS 100 10.0 Water 89.0
Example A12-11 wk 1.0 HS 100 10.0 Water 89.0
Example A12-12 wl 1.0 HS 100 10.0 Water 89.0
Example A12-13 wm 1.0 HS 100 10.0 Water 89.0
Example A12-14 wn 1.0 HS 100 10.0 Water 89.0
Example A12-15 wo 1.0 HS 100 10.0 Water 89.0
Example A12-16 wp 1.0 HS 100 10.0 Water 89.0
Example A12-17 wq 1.0 HS 100 10.0 Water 89.0
Example A12-18 wr 1.0 HS 100 10.0 Water 89.0
Example A12-19 ws 1.0 HS 100 10.0 Water 89.0
Example A12-20 wt 1.0 HS 100 10.0 Water 89.0
Example A12-21 wu 1.0 HS 100 10.0 Water 89.0
Example A12-22 wv 1.0 HS 100 10.0 Water 89.0
Example A12-23 ww 1.0 HS 100 10.0 Water 89.0
Example A12-24 wx 1.0 HS 100 10.0 Water 89.0
Example A12-25 wy 1.0 HS 100 10.0 Water 89.0
Example A12-26 wz 1.0 HS 100 10.0 Water 89.0
Example A12-27 xa 1.0 HS 100 10.0 Water 89.0
Example A12-28 xb 1.0 HS 100 10.0 Water 89.0
Example A12-29 xc 1.0 HS 100 10.0 Water 89.0
Example A12-30 xd 1.0 HS 100 10.0 Water 89.0
Example A12-31 xe 1.0 HS 100 10.0 Water 89.0
 
[TABLE-US-00040]
TABLE 40
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder 1 Binder 2 Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example A12-1 wa 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-2 wb 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-3 wc 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-4 wd 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-5 we 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-6 wf 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-7 wg 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-8 wh 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-9 wi 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-10 wj 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-11 wk 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-12 wl 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-13 wm 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-14 wn 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-15 wo 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-16 wp 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-17 wq 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-18 wr 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-19 ws 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-20 wt 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-21 wu 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-22 wv 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-23 ww 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-24 wx 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-25 wy 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-26 wz 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-27 xa 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-28 xb 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-29 xc 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-30 xd 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-31 xe 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
 
[TABLE-US-00041]
TABLE 41
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder 1 Binder 2 Active material Solvent
    Content   Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example A12-1 wa 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-2 wb 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-3 wc 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-4 wd 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-5 we 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-6 wf 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-7 wg 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-8 wh 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-9 wi 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-10 wj 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-11 wk 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-12 wl 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-13 wm 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-14 wn 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-15 wo 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-16 wp 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-17 wq 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-18 wr 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-19 ws 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-20 wt 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-21 wu 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-22 wv 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-23 ww 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-24 wx 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-25 wy 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-26 wz 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-27 xa 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-28 xb 0.2 HS100 2.0 PTFE 1-0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-29 xc 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-30 xd 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-31 xe 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
 

Comparative Examples A12-1 to A12-4

      According to materials and compositions of the carbon material dispersion liquid shown in Table 42, the carbon material dispersion varnish shown in Table 43, and the cathode mixture paste shown in Table 44, dispersion was performed in the same manner as in Example A12-2, and thereby a cell for cathode evaluation was assembled. In Comparative Example A12-4, a dispersant was not used.
[TABLE-US-00042]
TABLE 42
 
  Composition of carbon material dispersion liquid
  Dispersant     Solvent
  aqueous       Content
  solution       (%)
    Content Carbon   containing
    of active material   dispersant
    ingredient   Content   aqueous
  Type (%) Type (%) Type solution
 
Comparative xf 1.0 HS100 10.0 Water 89.0
Example A12-1            
Comparative xg 1.0 HS100 10.0 Water 89.0
Example A12-2            
Comparative xh 1.0 HS100 10.0 Water 89.0
Example A12-3            
Comparative Not 0 HS100 10.0 Water 90.0
Example A12-4 used
 
[TABLE-US-00043]
TABLE 43
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder 1 Binder 2 Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Comparative xf 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-1                    
Comparative xg 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-2                    
Comparative xh 0.6 HS100 6.0 PTFE 3.0 CMC 1.2 Water 90.4
Example A12-3                    
Comparative Not 0 HS100 6.0 PTFE 3.0 CMC 1.2 Water 91.0
Example A12-4 used                  
 
[TABLE-US-00044]
TABLE 44
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder 1 Binder 2 Active material Solvent
    Content   Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Ty pe (%) Type (%) Type (%)
 
Comparative xf 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-1                        
Comparative xg 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-2                        
Comparative xh 0.2 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.4
Example A12-3                        
Comparative Not 0 HS100 2.0 PTFE 1.0 CMC 0.4 LFP 54.0 Water 42.6
Example A12-4 used
 
      <Evaluation Results>
      All of the carbon material dispersion liquids, carbon material dispersion varnishes, and cathode mixture pastes prepared in Examples A12-1 to A12-31 were in a favorably dispersed state, and sedimentation or thickening did not occur even after the elapse of one month. Regarding the carbon material dispersion liquids, carbon material dispersion varnishes, and cathode mixture pastes of Comparative Examples A12-1 to A12-4, a viscosity was high and there were many coarse particles from the initial stage, but they were used as themselves for comparison. After the elapse of one month, the dispersed material had gelled.
      Because the triazine derivatives A to T have two hydroxyl groups and an acidic functional group which are directly attached to the triazine ring, they were thought to have sufficiently high hydrophilicity and excellent dispersibility. On the other hand, as compared to the above triazine derivatives, the triazine derivatives U to W were poorly dispersible in water because of their insufficient hydrophilicity.
      Using the cells for cathode evaluation of Examples A12-1 to A12-31 and Comparative Examples A12-1 to A12-4, and using the same method as Example A2-1, ionic resistance, reaction resistance, room temperature rate characteristic, low-temperature discharge characteristic were evaluated. The results are shown in Table 45.
[TABLE-US-00045]
TABLE 45
 
          Room Low-
          temperature temperature
    |Z|ion at |Z|ion at |Z|re at rate discharge
  Dispersant 25° C. −20° C. 25° C. characteristic characteristic
  Type [Ω] [Ω] [Ω] [%] [%]
 
 
Example A12-1 wa 10 418 6.3 71.5 79.2
Example A12-2 wb 10 416 6.1 72.0 80.1
Example A12-3 wc 10 418 6.2 71.3 79.5
Example A12-4 wd 14 491 8.5 62.1 63.4
Example A12-5 we 14 488 8.3 61.8 63.5
Example A12-6 wf 13 469 7.6 65.6 75.1
Example A12-7 wg 13 451 7.2 66.7 74.6
Example A12-8 wh 11 426 6.8 68.9 77.5
Example A12-9 wi 13 457 7.6 65.1 73.8
Example A12-10 wj 11 432 6.5 68.7 77.0
Example A12-11 wk 13 463 7.1 64.9 74.7
Example A12-12 wl 13 458 7.5 65.3 75.2
Example A12-13 wm 13 467 7.3 65.7 74.9
Example A12-14 wn 11 438 6.7 68.3 76.5
Example A12-15 wo 10 420 6.2 71.0 79.0
Example A12-16 wp 14 474 8.1 63.1 64.7
Example A12-17 wq 13 449 7.5 64.7 76.0
Example A12-18 wr 13 456 7.2 64.2 75.1
Example A12-19 ws 14 483 7.9 62.9 66.0
Example A12-20 wt 14 478 7.7 63.4 65.8
Example A12-21 wu 11 433 6.9 67.6 76.9
Example A12-22 wv 10 420 6.3 70.5 78.8
Example A12-23 ww 12 461 7.5 66.3 74.8
Example A12-24 wx 12 455 7.3 65.4 73.3
Example A12-25 wy 14 485 7.6 63.3 71.0
Example A12-26 wz 14 480 7.7 64.1 69.4
Example A12-27 xa 11 431 6.7 68.2 76.8
Example A12-28 xb 10 420 6.3 70.3 78.7
Example A12-29 xc 14 476 8.0 64.8 69.2
Example A12-30 xd 11 425 6.6 68.3 77.0
Example A12-31 xe 11 427 6.8 68.1 76.9
Comparative xf 18 640 12.0 53.4 55.2
Example A12-1            
Comparative xg 17 632 11.8 54.0 55.6
Example A12-2            
Comparative xh 16 625 11.5 54.8 56.1
Example A12-3            
Comparative Not 16 623 11.4 55.1 56.3
Example A12-4 used          
 
      Examples A12-1 to A12-31 were excellent regarding all characteristics, and it was confirmed that the same effects were obtained even in a case where an amine was an inorganic base and a solvent was water.

Second Example Group

      In Second Example Group, among the triazine derivatives represented by General Formula (1), a triazine derivative in which R 1 is a phenyl group having a substituent containing at least —NHC(═O)—, a benzimidazole group, an indole group which may have a substituent, or a pyrazole group which may have a substituent will be described.
      <Dispersant>
      Structures of the triazine derivatives A to Y represented by General Formula (1) of the present invention are shown below. A method for manufacturing the triazine derivatives A to Y represented by General Formula (1) used in the present invention is not particularly limited, and a well-known method can be applied. For example, a method described in JP2004-217842A can be applied. The disclosure by the above publication is partially incorporated in the present specification by reference.

(MOL) (CDX)
(MOL) (CDX)
(MOL) (CDX)
(MOL) (CDX)
      <Method for Manufacturing Dispersant Composed of Triazine Derivative and Amine>
      Dispersants a to ao shown in Table 46 were manufactured by methods described in the following examples.
[TABLE-US-00046]
TABLE 46
 
        Molar
        equivalent of
        amine with
        respect to
        triazine
  Dispersant Triazine derivative Amine derivative
 
Example B1-1 a Triazine derivative A Octylamine 1.0
Example B1-2 b Triazine derivative B Octylamine 1.0
Example B1-3 c Triazine derivative C Octylamine 1.0
Example B1-4 d Triazine derivative D Octylamine 1.0
Example B1-5 e Triazine derivative E Octylamine 1.0
Example B1-6 f Triazine derivative F Octylamine 1.0
Example B1-7 g Triazine derivative G Octylamine 1.0
Example B1-8 h Triazine derivative H Octylamine 1.0
Example B1-9 i Triazine derivative I Octylamine 1.0
Example B1-10 j Triazine derivative J Octylamine 1.0
Example B1-11 k Triazine derivative K Octylamine 1.0
Example B1-12 l Triazine derivative L Octylamine 1.0
Example B1-13 m Triazine derivative M Octylamine 1.0
Example B1-14 n Triazine derivative N Octylamine 1.0
Example B1-15 o Triazine derivative O Octylamine 1.0
Example B1-16 p Triazine derivative P Octylamine 1.0
Example B1-17 q Triazine derivative Q Octylamine 1.0
Example B1-18 r Triazine derivative R Octylamine 1.0
Example B1-19 s Triazine derivative S Octylamine 1.0
Example B1-20 t Triazine derivative T Octylamine 1.0
Example B1-21 u Triazine derivative U Octylamine 1.0
Example B1-22 v Triazine derivative V Octylamine 1.0
Example B1-23 w Triazine derivative W Octylamine 1.0
Example B1-24 x Triazine derivative X Octylamine 1.0
Example B1-25 y Triazine derivative Y Octylamine 1.0
Example B1-26 z Triazine derivative B Propylamine 1.0
Example B1-27 aa Triazine derivative B Stearylamine 1.0
Example B1-28 ab Triazine derivative B 2-Aminoethanol 1.0
Example B1-29 ac Triazine derivative B Dibutylamine 1.0
Example B1-30 ad Triazine derivative B Dioctylamine 1.0
Example B1-31 ae Triazine derivative B Distearylamine 1.0
Example B1-32 af Triazine derivative B Triethylamine 1.0
Example B1-33 ag Triazine derivative B Dimethyloctylamine 1.0
Example B1-34 ah Triazine derivative B Trioctylamine 1.0
Example B1-35 ai Triazine derivative B Dimethylstearylamine 1.0
Example B1-36 aj Triazine derivative B Triethanolamine 1.0
Example B1-37 ak Triazine derivative B Octylamine 0.1
Example B1-38 al Triazine derivative B Octylamine 0.3
Example B1-39 am Triazine derivative B Octylamine 0.5
Example B1-40 an Triazine derivative B Octylamine 2.0
Example B1-41 ao Triazine derivative B Octylamine 5.0
 

Example B1-1

      (Manufacture of Dispersant a)
      0.040 mol of the triazine derivative A was added to 200 g of water. 0.040 mol of octylamine was added thereto and stirred at 60° C. for 2 hours. After cooling to room temperature, filtration and purification were performed. The obtained residue was dried at 90° C. for 48 hours, and thereby a dispersant a was obtained.

Examples B1-2 to B1-25

      (Manufacture of Dispersants b to y)
      Dispersants b to y were obtained by manufacture in the same manner as in Example B1-1, except that triazine derivatives B to Y shown in Examples B1-2 to B1-25 in Table 46 were added instead of the triazine derivative A in the manufacture of the dispersant a.

Examples B1-26 to B1-36

      (Manufacture of Dispersants z to aj)
      Dispersants z to aj were obtained by manufacture in the same manner as in Example B1-2 except that amines shown in Examples B1-26 to B1-36 in Table 46 were added instead of octylamine in the manufacture of the dispersant b.

Examples B1-37 to B1-41

      (Manufacture of Dispersants ak to ao)
      Dispersants ak to ao were obtained by manufacture in the same manner as in Example B1-2 except that an amount of octylamine added in the manufacture of the dispersant b was changed to addition amounts which are shown in Examples B1-37 to B1-41 in Table 46.
      Structures of triazine derivatives AA to AC used in comparative examples are shown below. A method for manufacturing the triazine derivatives AA to AC used in the comparative examples is not particularly limited, and a well-known method can be applied. For example, a method described in JP2004-217842A can be applied. The disclosure by the above publication is partially incorporated in the present specification by reference.

(MOL) (CDX)
      Dispersants ba to bc shown in Table 47 were manufactured by methods described in the following comparative examples.
[TABLE-US-00047]
TABLE 47
 
        Molar
        equivalent of
        amine with
        respect to
    Triazine derivative   triazine
  Dispersant Amine Amine derivative
 
Example ba Triazine derivative Octylamine 1.0
B1-1   AA    
Example bb Triazine derivative Octylamine 1.0
B1-2   AB    
Example bc Triazine derivative Octylamine 1.0
B1-3   AC
 

Comparative Examples B1-1 to B1-3

      (Manufacture of Dispersants ba to bc)
      Dispersants ba to bc were obtained by manufacture in the same manner as in Example B1-1, except that the triazine derivatives AA to AC shown in Comparative Examples B1-1 to B1-3 in Table 47 were added instead of the triazine derivative A in the manufacture of the dispersant a.
      <Method for Manufacturing Dispersant Composed of Triazine Derivative and Inorganic Base>
      Dispersants ca to di shown in Table 48 were manufactured by methods described in the following examples.
[TABLE-US-00048]
TABLE 48
 
        Molar
        equivalent
        of inorganic
        base with
        respect to
  Disper-   Inorganic triazine
  sant Triazine derivative base derivative
 
Example B2-1 ca Triazine derivative A NaOH 0.5
Example B2-2 cb Triazine derivative B NaOH 0.5
Example B2-3 cc Triazine derivative C NaOH 0.5
Example B2-4 cd Triazine derivative D NaOH 0.5
Example B2-5 ce Triazine derivative E NaOH 0.5
Example B2-6 cf Triazine derivative F NaOH 0.5
Example B2-7 cg Triazine derivative G NaOH 0.5
Example B2-8 ch Triazine derivative H NaOH 0.5
Example B2-9 ci Triazine derivative I NaOH 0.5
Example B2-10 cj Triazine derivative J NaOH 0.5
Example B2-11 ck Triazine derivative K NaOH 0.5
Example B2-12 cl Triazine derivative L NaOH 0.5
Example B2-13 cm Triazine derivative M NaOH 0.5
Example B2-14 cn Triazine derivative N NaOH 0.5
Example B2-15 co Triazine derivative O NaOH 0.5
Example B2-16 cp Triazine derivative P NaOH 0.5
Example B2-17 cq Triazine derivative Q NaOH 0.5
Example B2-18 cr Triazine derivative R NaOH 0.5
Example B2-19 cs Triazine derivative S NaOH 0.5
Example B2-20 ct Triazine derivative T NaOH 0.5
Example B2-21 cu Triazine derivative U NaOH 0.5
Example B2-22 cv Triazine derivative V NaOH 0.5
Example B2-23 cw Triazine derivative W NaOH 0.5
Example B2-24 cx Triazine derivative X NaOH 0.5
Example B2-25 cy Triazine derivative Y NaOH 0.5
Example B2-26 cz Triazine derivative B Na2CO3 0.5
Example B2-27 da Triazine derivative B Li2CO3 0.5
Example B2-28 db Triazine derivative B K2CO3 0.5
Example B2-29 dc Triazine derivative B K3PO4 0.5
Example B2-30 dd Triazine derivative B Ca(OH)2 0.5
Example B2-31 de Triazine derivative B Mg(OH)2 0.5
Example B2-32 df Triazine derivative B NaOH 0.1
Example B2-33 dg Triazine derivative B NaOH 0.3
Example B2-34 dh Triazine derivative B NaOH 0.7
Example B2-35 di Triazine derivative B NaOH 1.0
 

Example B2-1

      (Manufacture of Dispersant ca)
      0.040 mol of the triazine derivative A was added to 200 g of water. 0.020 mol of sodium hydroxide was added thereto and stirred at 60° C. for 2 hours. After cooling to room temperature, filtration and purification were performed. The obtained residue was dried at 90° C. for 48 hours, and thereby a dispersant ca was obtained.

Examples B2-2 to B2-25

      (Manufacture of Dispersants cb to cy)
      Dispersants cb to cy were obtained by manufacture in the same manner as in Example B2-1, except that triazine derivatives B to Y shown in Examples B2-2 to B2-25 in Table 48 were added instead of the triazine derivative A in the manufacture of the dispersant ca.

Examples B2-26 to B2-31

      (Manufacture of Dispersants cz to de)
      Dispersants cz to de were obtained by manufacture in the same manner as in Example B2-2 except that inorganic bases shown in Examples B2-26 to B2-31 in Table 48 were added instead of sodium hydroxide in the manufacture of the dispersant cb.

Examples B2-32 to B2-35

      (Manufacture of Dispersants df to di)
      Dispersants df to di were obtained by manufacture in the same manner as in Example B2-2 except that an amount of sodium hydroxide added in the manufacture of the dispersant cb was changed to addition amounts which are shown in Examples B2-32 to B2-35 in Table 48.
      Dispersants ea to ec shown in Table 49 were manufactured by methods described in the following comparative examples.
[TABLE-US-00049]
TABLE 49
 
        Molar
        equivalent of
        inorganic base
        with respect
      Inorganic to triazine
  Dispersant Triazine derivative base derivative
 
Comparative ea Triazine derivative NaOH 0.5
Example B2-1   AA    
Comparative eb Triazine derivative NaOH 0.5
Example B2-2   AB    
Comparative ec Triazine derivative NaOH 0.5
Example B2-3   AC
 

Comparative Examples B2-1 to B2-3

      (Manufacture of Dispersants ea to ec)
      Dispersants ea to ec were obtained by manufacture in the same manner as in Example B2-1, except that the triazine derivatives AA to AC shown in Comparative Examples B2-1 to B2-3 in Table 49 were added instead of the triazine derivative A in the manufacture of the dispersant ca.
      The carbon material dispersion liquids, carbon material dispersion varnishes, and mixture pastes shown in the examples and comparative examples were produced using the following materials.

Example B3-1

      <Preparation of Carbon Material Dispersion Liquid>
      According to the composition shown in Table 50, N-methyl-2-pyrrolidone and the dispersant a were added to a glass bottle and mixed. Thereafter, a carbon material was added thereto and dispersed with a paint conditioner for 2 hours using zirconia beads as media. Thereby, a carbon material dispersion liquid containing the dispersant a was obtained.
      <Preparation of Carbon Material Dispersion Varnish>
      According to the composition shown in Table 50, the prepared carbon material dispersion liquid containing the dispersant a was mixed with a binder and N-methyl-2-pyrrolidone with a disper. Thereby, a carbon material dispersion varnish was obtained.
      <Preparation of Cathode Mixture Paste>
      According to the composition shown in Table 50, the prepared carbon material dispersion varnish containing the dispersant a was mixed with an active material and N-methyl-2-pyrrolidone with a disper. Thereby, a cathode mixture paste was obtained.
      <Production of Electrode>
      The prepared cathode mixture paste containing the dispersant a was applied onto an aluminum foil having a thickness of 20 μm using a doctor blade, and then dried at 120° C. for 30 minutes under reduced pressure. Thereafter, the aluminum foil was rolled with a roller pressing machine. Thereby, an electrode having an application amount of 17 mg/cm 2 and a density of 3.0 g/cm 3 was produced. An electrode having a uniform thickness and density was obtained.
      <Assembly of Cell for Evaluation Cathode of Lithium Ion Secondary Battery>
      The produced electrode containing the dispersant a was punched out to a diameter of 16 mm to be used as a cathode, and a metallic lithium foil (a thickness of 0.15 mm) was used as an anode. A separator made of a porous polypropylene film (a thickness of 20 μm, and a porosity of 50%) was inserted and laminated between the cathode and the anode, and was filled with 0.1 ml of an electrolyte solution (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate was mixed at a volume ratio of 1:1). Thereby, a closed bipolar metal cell (HS Flat Cell manufactured by Hohsen Corp.) was assembled. The cell was assembled in a glove box purged with argon gas.
[TABLE-US-00050]
TABLE 50
 
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Composition of a 0.2 HS100 10.0         NMP 89.8
carbon material                    
dispersion liquid                    
Composition of   0.12   6.0 PVDF 6.0       87.9
carbon material                    
dispersion varnish                    
Composition of   0.04   2.0   2.0 NMC 54.0   42.0
cathode mixture                    
paste
 

[Examples B3-2 to B3-76] Comparison 1 of Dispersant Types

      A cell for cathode evaluation was assembled by dispersion with the same composition and in the same manner as in Example B3-1 except that the dispersants b to ao and ca to di shown in Table 51 were used instead of the dispersant a.
[TABLE-US-00051]
TABLE 51
 
    Dispersant
 
  Example B3-2 b
  Example B3-3 c
  Example B3-4 d
  Example B3-5 e
  Example B3-6 f
  Example B3-7 g
  Example B3-8 h
  Example B3-9 i
  Example B3-10 j
  Example B3-11 k
  Example B3-12 l
  Example B3-13 m
  Example B3-14 n
  Example B3-15 o
  Example B3-16 p
  Example B3-17 q
  Example B3-18 r
  Example B3-19 s
  Example B3-20 t
  Example B3-21 u
  Example B3-22 v
  Example B3-23 w
  Example B3-24 x
  Example B3-25 y
  Example B3-26 z
  Example B3-27 aa
  Example B3-28 ab
  Example B3-29 ac
  Example B3-30 ad
  Example B3-31 ae
  Example B3-32 af
  Example B3-33 ag
  Example B3-34 ah
  Example B3-35 ai
  Example B3-36 aj
  Example B3-37 ak
  Example B3-38 al
  Example B3-39 am
  Example B3-40 an
  Example B3-41 ao
  Example B3-42 ca
  Example B3-43 cb
  Example B3-44 cc
  Example B3-45 cd
  Example B3-46 ce
  Example B3-47 cf
  Example B3-48 cg
  Example B3-49 ch
  Example B3-50 ci
  Example B3-51 cj
  Example B3-52 ck
  Example B3-53 cl
  Example B3-54 cm
  Example B3-55 cn
  Example B3-56 co
  Example B3-57 cp
  Example B3-58 cq
  Example B3-59 cr
  Example B3-60 cs
  Example B3-61 ct
  Example B3-62 cu
  Example B3-63 cv
  Example B3-64 cw
  Example B3-65 cx
  Example B3-66 cy
  Example B3-67 cz
  Example B3-68 da
  Example B3-69 db
  Example B3-70 dc
  Example B3-71 dd
  Example B3-72 de
  Example B3-73 df
  Example B3-74 dg
  Example B3-75 dh
  Example B3-76 di
 

[Comparative Examples B3-1 to B3-7] Comparison 2 of Dispersant Types

      A cell for cathode evaluation was assembled by dispersion in the same manner as in Example B3-1 except that the dispersants ba to be and ea to ec shown in Table 52 were used. However, in Comparative Example B3-7, a dispersant was not used, and a composition for a dispersant was changed to a solvent.
[TABLE-US-00052]
  TABLE 52
   
    Dispersant
   
  Comparative Example B3-1 ba
  Comparative Example B3-2 bb
  Comparative Example B3-3 bc
  Comparative Example B3-4 ea
  Comparative Example B3-5 eb
  Comparative Example B3-6 ec
  Comparative Example B3-7 Not used
   
      <Evaluation of Ionic Resistance>
      The cell for cathode evaluation assembled in Examples B3-1 to B3-76 and Comparative Examples B3-1 to B3-7 was allowed to stand in a constant-temperature tank at −20° C. for 12 hours. An AC impedance was measured at an open circuit potential with a frequency of 0.1 Hz and an amplitude of 10 mV to obtain an ionic resistance 14.. Subsequently, the cell for cathode evaluation was moved into room temperature (25° C.) and allowed to stand for 3 hours, and the impedance was measured in the same manner to obtain the ionic resistance |Z| ion. An impedance analyzer was used for the measurement.
      <Evaluation of Reaction Resistance>
      Following the evaluation of ionic resistance, using a charge and discharge measuring device, a total of 5 cycles were carried out, with one cycle being charging and discharging in which full charging was performed with 0.1C constant current-constant voltage charging (an upper limit voltage of 4.2V) at room temperature, and discharging was performed with a constant current of 0.1C to a discharge lower limit voltage of 3.0V. 0.1C discharge capacity at the fifth cycle was recorded. Next, the cell for cathode evaluation in a state of being discharged to 3.0V was connected to an impedance analyzer, and AC impedance measurement was performed at 3.0V, an amplitude of 10 mV, and a frequency from 0.1 Hz to 1 MHz. When the results were plotted on the complex plane by a Cole-Cole plot method, a semicircular curve was obtained. A diameter of an arc was defined as a reaction resistance |Z| re of the active material.
      <Evaluation of Room Temperature Rate Characteristic and Low-Temperature Discharge Characteristic>
      Next, after full charging with 0.1C at room temperature, discharging was performed with a constant current of 0.5C to a discharge lower limit voltage of 3.0V, full charging was performed again with 0.1C, and then discharging was performed with a constant current of 5C to 3.0V. A ratio of 5C discharge capacity to 0.1C discharge capacity at the fifth cycle recorded in a test of reaction resistance evaluation was defined as a room temperature rate characteristic (%). In addition, a 0.5C discharge capacity at room temperature was recorded. Subsequently, full charging was performed with 0.1C at room temperature in the same manner. Thereafter, the battery was transferred to a −20° C. constant-temperature tank, left for 12 hours, and then discharged with a constant current of 0.5C. A ratio of 0.5C discharge capacity at −20° C. to 0.5C discharge capacity at room temperature was defined as a low-temperature discharge characteristic (%). As the room temperature rate characteristic and low-temperature discharge characteristic become closer to 100%, the characteristics become more favorable.
      <Evaluation Results>
      The carbon material dispersion liquids, carbon material dispersion varnishes, and cathode mixture pastes shown in Examples B3-1 to B3-76 and Comparative Examples B3-1 to B3-6 were in a favorably dispersed state, and sedimentation or thickening did not occur even after the elapse of one month. Regarding the carbon material dispersion liquid, carbon material dispersion varnish, and cathode mixture paste of Comparative Example B3-7 in which a dispersant was not used, a viscosity was considerably high and fluidity was inferior from the initial stage, but they were used as themselves for comparison. In addition, after the elapse of one month, the dispersed material had gelled.
      Table 53-1 and Table 53-2 show evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of the cell for cathode evaluation of Examples B3-1 to B3-76 and Comparative Examples B3-1 to B3-7.
[TABLE-US-00053]
TABLE 53-1
 
          Room Low-
          temperature temperature
    |Z|ion at |Z|ion at |Z|re at rate discharge
  Dispersant 25° C. −20° C. 25° C. characteristic characteristic
  Type [Ω] [Ω] [Ω] [%] [%]
 
Example B3-1 a 10 427 5.2 68.8 75.5
Example B3-2 b 10 421 4.9 69.1 76.0
Example B3-3 c 10 423 5.3 68.9 75.8
Example B3-4 d 10 425 5.3 68.3 75.4
Example B3-5 e 11 445 6.2 67.6 73.5
Example B3-6 f 14 485 8.0 63.3 65.0
Example B3-7 g 12 455 7.3 66.1 70.5
Example B3-8 h 13 475 7.8 64.5 64.2
Example B3-9 i 14 490 8.1 63.0 63.8
Example B3-10 j 12 460 7.5 65.8 70.1
Example B3-11 k 14 493 8.5 62.3 63.4
Example B3-12 l 14 489 8.1 62.8 64.3
Example B3-13 m 13 480 7.9 64.6 66.4
Example B3-14 n 14 487 8.2 62.7 64.7
Example B3-15 o 11 440 6.1 67.5 71.8
Example B3-16 p 12 459 7.2 64.9 70.1
Example B3-17 q 13 482 7.7 63.8 64.4
Example B3-18 r 12 462 7.4 65.2 68.9
Example B3-19 s 11 447 6.3 66.6 71.9
Example B3-20 t 12 463 7.3 65.3 69.2
Example B3-21 u 13 479 7.8 63.7 66.6
Example B3-22 v 12 467 7.5 65.5 69.3
Example B3-23 w 11 443 6.4 66.8 72.0
Example B3-24 x 13 477 7.9 63.6 67.5
Example B3-25 y 11 445 6.1 66.5 72.6
Example B3-26 z 10 422 5.1 68.7 75.9
Example B3-27 aa 10 423 5.0 68.8 75.0
Example B3-28 ab 10 421 5.3 68.9 74.5
Example B3-29 ac 10 423 5.2 68.6 74.6
Example B3-30 ad 10 422 5.1 69.0 74.8
Example B3-31 ae 10 423 5.1 68.5 75.1
Example B3-32 af 10 424 5.3 68.8 75.3
Example B3-33 ag 10 421 5.0 68.4 75.8
Example B3-34 ah 10 423 5.2 68.7 74.5
Example B3-35 ai 10 422 5.3 68.3 75.3
Example B3-36 aj 10 421 5.3 68.8 75.7
Example B3-37 ak 12 429 7.1 65.2 69.4
Example B3-38 al 10 425 5.2 68.1 74.7
Example B3-39 am 10 426 5.0 68.7 75.8
Example B3-40 an 11 427 6.4 67.0 72.5
 
[TABLE-US-00054]
TABLE 53-2
 
          Room Low-
          temperature temperature
    |Z|ion at |Z|ion at |Z|re at rate discharge
  Dispersant 25° C. −20° C. 25° C. characteristic characteristic
  Type [Ω] [Ω] [Ω] [%] [%]
 
 
Example B3-41 ao 12 440 7.3 64.9 68.5
Example B3-42 ca 10 424 5.2 68.4 74.9
Example B3-43 cb 10 420 5.0 69.1 76.0
Example B3-44 cc 10 423 5.1 68.7 74.6
Example B3-45 cd 10 426 5.2 68.3 74.8
Example B3-46 ce 11 445 6.2 67.1 73.0
Example B3-47 cf 14 486 8.0 63.1 63.9
Example B3-48 cg 12 463 7.4 66.0 68.8
Example B3-49 ch 13 480 7.7 63.9 66.5
Example B3-50 ci 14 487 8.2 62.9 63.7
Example B3-51 cj 12 468 7.6 65.9 68.9
Example B3-52 ck 14 493 8.5 62.3 63.4
Example B3-53 cl 14 489 8.1 62.4 64.6
Example B3-54 cm 13 476 7.8 63.8 66.8
Example B3-55 cn 14 485 8.3 62.8 63.9
Example B3-56 co 11 443 6.1 66.9 74.9
Example B3-57 cp 12 467 7.7 65.7 69.1
Example B3-58 cq 13 478 7.9 64.0 67.0
Example B3-59 cr 12 465 7.4 65.2 68.8
Example B3-60 cs 11 444 6.3 67.0 74.5
Example B3-61 ct 12 460 7.5 64.9 69.6
Example B3-62 cu 13 481 7.6 64.3 67.2
Example B3-63 cv 12 458 7.2 65.8 70.3
Example B3-64 cw 11 442 6.2 66.7 75.1
Example B3-65 cx 13 482 7.7 64.6 66.8
Example B3-66 cy 11 440 6.3 66.6 75.3
Example B3-67 cz 10 422 5.4 68.9 75.8
Example B3-68 da 10 425 5.1 68.5 75.2
Example B3-69 db 10 429 5.2 68.0 74.6
Example B3-70 dc 10 430 5.3 68.1 74.7
Example B3-71 dd 11 441 6.4 66.8 75.8
Example B3-72 de 11 445 6.5 67.6 75.9
Example B3-73 df 11 443 6.4 68.0 73.5
Example B3-74 dg 10 420 5.1 68.8 75.8
Example B3-75 dh 10 421 5.2 68.6 75.5
Example B3-76 di 11 442 6.5 68.2 72.6
Comparative ba 17 515 9.5 53.4 42.1
Example B3-1            
Comparative bb 18 530 10.1 50.6 37.2
Example B3-2            
Comparative bc 17 517 9.3 52.7 43.0
Example B3-3            
Comparative ea 17 520 9.4 52.6 39.7
Example B3-4            
Comparative eb 18 526 9.9 50.1 40.1
Example B3-5            
Comparative ec 17 518 9.6 52.9 43.3
Example B3-6            
Comparative Not 16 507 9.2 54.4 44.9
Example B3-7 used
 
      As can be seen from Tables 53-1 and 53-2, the cathodes of Examples B3-1 to B3-76 in which the dispersants a to ao and ca to di were used were extremely excellent in the all ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic at room temperature and −20° C., as compared to the cathodes of Comparative Example B3-7 in which a dispersant was not used, and Comparative Examples B3-1 to B3-6 in which the dispersants ba to be and ea to ec were used.
      The reason for this is thought to be that, because Li + with extremely high electron density is present near the dispersants a to ao and ca to di, dielectric polarization occurs, and thereby the dispersants have a high dielectric constant in a battery. It is considered that, accordingly, ionic conductivity is improved, and desolvation energy and solvation energy of Li + when an active material reacts with Li are reduced. As a result, ionic resistance and reaction resistance are reduced, and therefore characteristics in terms of the whole battery is also improved.

[Examples B4-1 to B4-5] [Comparative Examples B4-1 to B4-5] Comparison of Carbon Material Types

      According to materials and compositions of the carbon material dispersion liquid shown in Table 54, the carbon material dispersion varnish shown in Table 55, and the cathode mixture paste shown in Table 56, dispersion was performed in the same manner as in Example B3-1, and thereby a cell for cathode evaluation was assembled. Because a large amount of dispersant is required for carbon materials with a high specific surface area, an appropriate amount to be used was determined according to each carbon material.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00055]
TABLE 54
 
  Composition of carbon material dispersion liquid
  Dispersant Carbon material Solvent
    Content   Content   Content
  Type (%) Type (%) Type (%)
 
Example B4-1 b 0.4 super-P 10.0 NMP 89.6
Example B4-2 b 0.4 M800 10.0 NMP 89.6
Example B4-3 b 1.0 EC-300J 10.0 NMP 89.0
Example B4-4 b 1.5 CNT 3.0 NMP 95.5
Example B4-5 b 0.2 VGCF 10.0 NMP 89.8
Comparative ba 0.4 super-P 10.0 NMP 89.6
Example B4-1            
Comparative ba 0.4 M800 10.0 NMP 89.6
Example B4-2            
Comparative ba 1.0 EC-300J 10.0 NMP 89.0
Example B4-3            
Comparative ba 1.5 CNT 3.0 NMP 95.5
Example B4-4            
Comparative ba 0.2 VGCF 10.0 NMP 89.8
Example B4-5
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00056]
TABLE 55
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder Solvent
    Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%)
 
Example B4-1 b 0.24 super-P 6.0 PVDF 6.0 NMP 87.8
Example B4-2 b 0.24 M800 6.0 PVDF 6.0 NMP 87.8
Example B4-3 b 0.6 EC-300J 6.0 PVDF 6.0 NMP 87.4
Example B4-4 b 1.45 CNT 2.9 PVDF 2.9 NMP 92.8
Example B4-5 b 0.12 VGCF 6.0 PVDF 6.0 NMP 87.9
Comparative ba 0.24 super-P 6.0 PVDF 6.0 NMP 87.8
Example B4-1                
Comparative ba 0.24 M800 6.0 PVDF 6.0 NMP 87.8
Example B4-2                
Comparative ba 0.6 EC-300J 6.0 PVDF 6.0 NMP 87.4
Example B4-3                
Comparative ba 1.45 CNT 2.9 PVDF 2.9 NMP 92.8
Example B4-4                
Comparative ba 0.12 VGCF 6.0 PVDF 6.0 NMP 87.9
Example B4-5                
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00057]
TABLE 56
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example B4-1 b 0.08 super-P 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example B4-2 b 0.08 M800 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example B4-3 b 0.2 EC-300J 2.0 PVDF 2.0 NMC 54.0 NMP 41.8
Example B4-4 b 0.650 CNT 1.3 PVDF 1.3 NMC 54.0 NMP 42.8
Example B4-5 b 0.04 VGCF 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Comparative ba 0.08 super-P 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example B4-1                    
Comparative ba 0.08 M800 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example B4-2                    
Comparative ba 0.2 EC-300J 2.0 PVDF 2.0 NMC 54.0 NMP 41.8
Example B4-3                    
Comparative ba 0.650 CNT 1.3 PVDF 1.3 NMC 54.0 NMP 42.8
Example B4-4                    
Comparative ba 0.04 VGCF 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B4-5                    
 
      <Evaluation Results>
      The carbon material dispersion liquids, carbon material dispersion varnishes, and cathode mixture pastes shown in all of the examples and comparative examples were also in a favorably dispersed state, and sedimentation or thickening did not occur even after the elapse of one month.
      Table 57 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of the cell for cathode evaluation of Examples B4-1 to B4-5 and Comparative Examples B4-1 to B4-5.
[TABLE-US-00058]
TABLE 57
 
          Room Low-
          temperature temperature
  Carbon |Z|ion at |Z|ion at |Z|re at rate discharge
  material 25° C. −20° C. 25° C. characteristic characteristic
  Type [Ω] [Ω] [Ω] [%] [%]
 
 
Example B4-1 super-P 10 423 5.1 68.6 75.7
Example B4-2 M800 11 446 6.4 66.9 72.0
Example B4-3 EC-300J 12 462 7.3 65.7 69.2
Example B4-4 CNT 10 422 5.2 68.8 76.0
Example B4-5 VGCF 12 459 7.5 65.9 68.9
Comparative super-P 17 612 10.7 51.9 42.4
Example B4-1            
Comparative M800 17 618 10.8 52.5 43.2
Example B4-2            
Comparative EC-300J 18 625 10.9 50.3 37.1
Example B4-3            
Comparative CNT 18 628 11.1 49.1 36.7
Example B4-4            
Comparative VGCF 16 609 10.3 54.6 45.3
Example B4-5            
 
      The same effects were confirmed for all the carbon materials. Differences between Examples B4-1 to B4-5 were thought to be differences due to conductivities of the carbon materials. In addition, in Comparative Examples B4-1 to B4-5, there was a tendency in which as an amount of dispersant added became larger, resistance became higher, which is an inferior characteristic.
      Based on the above verification, it was confirmed that the above-described effects were not dependent on the type of carbon material.

[Examples B5-1 to B5-6] Comparison 1 of Amount of Dispersant Per Active Material Surface Area

      A cell for cathode evaluation was assembled in the same manner except that dispersant amounts shown in Table 58, Table 59, and Table 60 were used instead of the dispersant amount in Example B3-2. Table 61 shows a dispersant amount (mg) with respect to 1 m 2 active material surface area in the electrode.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00059]
TABLE 58
 
  Composition of carbon material dispersion liquid
  Dispersant Carbon material Solvent
    Content   Content   Content
  Type (%) Type (%) Type (%)
 
Comparative Not 0 HS100 10.0 NMP 90.0
Example B3-7 used          
Example B5-1 b 0.01 HS100 10.0 NMP 90.0
Example B5-2 b 0.02 HS100 10.0 NMP 90.0
Example B5-3 b 0.05 HS100 10.0 NMP 90.0
Example B5-4 b 0.1 HS100 10.0 NMP 89.9
Example B3-2 b 0.2 HS100 10.0 NMP 89.8
Example B5-5 b 0.4 HS100 10.0 NMP 89.6
Example B5-6 b 0.8 HS100 10.0 NMP 89.2
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00060]
TABLE 59
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder Solvent
    Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%)
 
Comparative Not 0 HS100 6.0 PVDF 6.0 NMP 88.0
Example B3-7 used              
Example B5-1 b 0.006 HS100 6.0 PVDF 6.0 NMP 88.0
Example B5-2 b 0.012 HS100 6.0 PVDF 6.0 NMP 88.0
Example B5-3 b 0.03 HS100 6.0 PVDF 6.0 NMP 88.0
Example B5-4 b 0.06 HS100 6.0 PVDF 6.0 NMP 87.9
Example B3-2 b 0.12 HS100 6.0 PVDF 6.0 NMP 87.9
Example B5-5 b 0.24 HS100 6.0 PVDF 6.0 NMP 87.8
Example B5-6 b 0.48 HS100 6.0 PVDF 6.0 NMP 87.5
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00061]
TABLE 60
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Comparative Not 0 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B3-7 used                  
Example B5-1 b 0.002 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B5-2 b 0.004 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B5-3 b 0.01 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B5-4 b 0.02 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B3-2 b 0.04 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 42.0
Example B5-5 b 0.08 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 41.9
Example B5-6 b 0.16 HS100 2.0 PVDF 2.0 NMC 54.0 NMP 41.8
 
      (Amount of Dispersant Per Active Material Surface Area)
[TABLE-US-00062]
  TABLE 61
   
    Dispersant amount per active
    material surface area (mg/m2)
   
 
  Comparative 0
  Example B3-7  
  Example B5-1 0.06
  Example B5-2 0.12
  Example B5-3 0.30
  Example B5-4 0.60
  Example B3-2 1.19
  Example B5-5 2.39
  Example B5-6 4.78
   
      <Evaluation Results>
      Table 62 shows evaluation results of reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Comparative Example B3-7, Example B3-2, and Examples B5-1 to B5-6.
[TABLE-US-00063]
TABLE 62
 
  Dispersant   Room Low-
  amount per   temperature temperature
  active |Z|re at rate discharge
  material 25° C. characteristic characteristic
  surface area [Ω] [%] [%]
 
 
Comparative 0 10.2 54.4 44.9
Example B3-7        
Example B5-1 0.06 8.0 64.7 66.7
Example B5-2 0.12 7.2 64.9 69.3
Example B5-3 0.30 6.8 66.8 73.2
Example B5-4 0.60 6.3 67.2 72.6
Example B3-2 1.19 4.9 69.1 76.0
Example B5-5 2.39 4.8 69.3 76.7
Example B5-6 4.78 4.8 69.6 77.1
 
      Based on Example B5-1, it was found that when a dispersant amount with respect to the active material surface area was too small, the effect was diminished. A particularly excellent effect was obtained when a dispersant amount became larger than that of Example B5-2, and the effect was gradually improved as the dispersant amount increased.

[Examples B6-1 to B6-9] Comparison 2 of Amount of Dispersant Per Active Material Surface Area

      Dispersion was performed in the same manner as in Example B3-2 with materials and compositions shown in Table 63, Table 64, and Table 65, and thereby a cell for cathode evaluation was produced. Table 66 shows a dispersant amount (mg) with respect to 1 m 2 active material surface area in the electrode.
      (Composition of Carbon Material Dispersion Liquids)
[TABLE-US-00064]
TABLE 63
 
  Composition of carbon material dispersion liquid
  Dispersant Carbon material Solvent
    Content   Content   Content
  Type (%) Type (%) Type (%)
 
Example B6-1 b 0.66 CNT 6.6 NMP 92.7
Example B6-2 b 1.98 CNT 6.6 NMP 91.4
Example B6-3 b 3.3 CNT 6.6 NMP 90.1
Example B6-4 b 6.6 CNT 6.6 NMP 86.8
Example B6-5 b 9.9 CNT 6.6 NMP 83.5
Example B6-6 b 11.6 CNT 6.6 NMP 81.9
Example B6-7 b 13.2 CNT 6.6 NMP 80.2
Example B6-8 b 14.9 CNT 6.6 NMP 78.6
Example B6-9 b 16.5 CNT 6.6 NMP 76.9
 
      (Composition of Carbon Material Dispersion Varnishes)
[TABLE-US-00065]
TABLE 64
 
  Composition of carbon material dispersion varnish
  Dispersant Carbon material Binder Solvent
    Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%)
 
Example B6-1 b 0.62 CNT 6.2 PVDF 5.0 NMP 88.2
Example B6-2 b 1.86 CNT 6.2 PVDF 5.0 NMP 86.9
Example B6-3 b 3.1 CNT 6.2 PVDF 5.0 NMP 85.7
Example B6-4 b 6.2 CNT 6.2 PVDF 5.0 NMP 82.6
Example B6-5 b 9.3 CNT 6.2 PVDF 5.0 NMP 79.5
Example B6-6 b 10.9 CNT 0.2 PVDF 5.0 NMP 78.0
Example B6-7 b 12.4 CNT 6.2 PVDF 5.0 NMP 76.4
Example B6-8 b 14.0 CNT 6.2 PVDF 5.0 NMP 74.9
Example B6-9 b 15.5 CNT 6.2 PVDF 5.0 NMP 73.3
 
      (Composition of Cathode Mixture Pastes)
[TABLE-US-00066]
TABLE 65
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example B6-1 b 0.31 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 44.1
Example B6-2 b 0.93 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 43.5
Example B6-3 b 1.6 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 42.9
Example B6-4 b 3.1 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 41.3
Example B6-5 b 4.7 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 39.8
Example B6-6 b 5.4 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 39.0
Example B6-7 b 6.2 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 38.2
Example B6-8 b 7.0 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 37.4
Example B6-9 b 7.8 CNT 3.1 PVDF 2.5 NMC 50.0 NMP 36.7
 
      (Amount of Dispersant Per Active Material Surface Area)
[TABLE-US-00067]
  TABLE 66
   
    Dispersant amount per active
    material surface area (mg/m2)
   
 
  Example B6-1 10
  Example B6-2 30
  Example B6-3 50
  Example B6-4 100
  Example B6-5 150
  Example B6-6 175
  Example B6-7 200
  Example B6-8 225
  Example B6-9 250
   
      <Evaluation Results>
      Table 67 shows evaluation results of reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example B6-1 to Example B6-9.
[TABLE-US-00068]
TABLE 67
 
  Dispersant   Room Low-
  amount per   temperature temperature
  active material |Z|re at rate discharge
  surface area 25° C. characteristic characteristic
  (mg/m2) [Ω] [%] [%]
 
 
Example B6-1 10 6.2 66.7 72.1
Example B6-2 30 6.1 66.5 72.5
Example B6-3 50 5.4 68.2 75.5
Example B6-4 100 5.4 68.1 75.8
Example B6-5 150 5.5 68.0 75.3
Example B6-6 175 6.2 66.8 71.9
Example B6-7 200 7.0 65.3 70.1
Example B6-8 225 7.6 63.6 67.4
Example B6-9 250 7.7 64.1 66.8
 
      Based on Table 67, it was found that when a dispersant amount exceeded the dispersant amount in Example B6-6, an effect of reducing reaction resistance was diminished. The reason for this was thought to be that, when a dispersant amount was in excess, the adverse effect of a resistance component becoming larger than an amount of reduction in desolvation energy.
      Based on the above results, it was found that there is an optimum range of an amount of dispersant added to the active material surface area for obtaining an excellent effect of reducing reaction resistance.

[Examples B7-1 to B7-6] Comparison 1 of Amount of Dispersant with Respect to Amount of Electrolyte Solution

      A cell for cathode evaluation was assembled in the same manner as in Example B5-2, except that an amount of an electrolyte solution was changed to an amount shown in Table 68 using the cathode produced in Example B5-2.
[TABLE-US-00069]
TABLE 68
 
  Electrolyte solution Dispersant amount with respect
  amount added in cell to electrolyte solution
  (ml) amount(mg/ml)
 
 
Example B7-1 0.05 0.12
Example B5-2 0.1 0.059
Example B7-2 0.2 0.023
Example B7-3 0.4 0.015
Example B7-4 0.6 0.010
Example B7-5 0.7 0.007
Example B7-6 1.2 0.005
 

[Examples B8-1 to B8-7] Comparison 2 of Amount of Dispersant with Respect to Amount of Electrolyte Solution

      A cathode was produced in the same manner as in Example B6-3 except that the cathode mixture paste produced in Example B6-3 was used, and a coating amount was changed to 28 mg/cm 2. In addition, a cell for cathode evaluation was assembled in the same manner as in Example B6-3 except that an amount of electrolyte solution added to the cell for cathode evaluation was changed to an amount shown in Table 69.
[TABLE-US-00070]
TABLE 69
 
  Electrolyte solution Dispersant amount with respect
  amount added in cell to electrolyte solution amount
  (ml) (mg/ml)
 
 
Example B8-1 0.03 99.1
Example B8-2 0.04 74.3
Example B8-3 0.05 59.4
Example B8-4 0.06 49.3
Example B8-5 0.08 37.2
Example B8-6 0.1 29.7
Example B8-7 0.2 14.9
 
      <Evaluation Results>
      Table 70 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example B5-2, Examples B7-1 to B7-6, and Comparative Example B3-7. Table 71 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example B8-1 to Example B8-7.
      The reaction resistances of Example B5-2 and Examples B7-1 to B7-6 were all the same level. The reason for this is thought to be that amounts of dispersant with respect to the active material surface area were the same.
      In addition, ionic resistance at room temperature and low temperature greatly became lower in Examples B7-1 to B7-4 than that of Comparative Example B3-7, and the effects were poor in Examples B7-5 and B7-6 with Example B7-4 as the lower limit. It was shown that there is a lower limit of an optimum amount of dispersant with respect to an amount of electrolyte solution for obtaining an excellent effect.
      Because room temperature rate characteristic and low-temperature discharge characteristic are affected by both ionic resistance and reaction resistance, there is a need for a design in which both effects can be obtained, in order to obtain excellent characteristics in a battery.
      Meanwhile, from the comparison between Examples B8-1 to B8-7, it was found that the effect of reducing ionic resistance was diminished even when an amount of dispersant was too large with respect to an amount of electrolyte solution. The reason for this is thought to be that because the dispersant is an insulating compound, when an amount thereof is in excess, the dispersant becomes a resistance component itself.
      Based on the above results, it was found that there is also an upper limit to an optimum amount of dispersant with respect to an amount of electrolyte solution.
[TABLE-US-00071]
TABLE 70
 
  Dispersant          
  amount with       Room Low-
  respect to       temperature temperature
  electrolyte |Z|ion at |Z|ion at |Z|re at rate discharge
  solution amount 25° C. −20° C. 25° C. characteristic characteristic
  (mg/ml) [Ω] [Ω] [Ω] [%] [%]
 
 
Example B7-1 0.12 12 460 7.1 66.6 71.1
Example B5-2 0.059 12 462 7.2 64.9 69.3
Example B7-2 0.023 12 460 7.2 65.2 70.1
Example B7-3 0.015 12 458 7.2 65.3 70.3
Example B7-4 0.010 12 455 7.3 64.9 70.5
Example B7-5 0.007 13 482 7.3 64.5 67.5
Example B7-6 0.005 13 479 7.3 64.1 67.1
Comparative 0 16 607 10.2 54.4 44.9
Example B3-7            
 
[TABLE-US-00072]
TABLE 71
 
  Dispersant          
  amount with       Room Low-
  respect to       temperature temperature
  electrolyte |Z|ion at |Z|ion at |Z|re at rate discharge
  solution amount 25° C. −20° C. 25° C. characteristic characteristic
  (mg/ml) [Ω] [Ω] [Ω] [%] [%]
 
 
Example B8-1 99.1 13 482 7.2 63.8 66.3
Example B8-2 74.3 13 479 7.1 64.2 67.1
Example B8-3 59.4 10 426 7.1 68 75.2
Example B8-4 49.3 10 423 7.0 68.3 75.5
Example B8-5 37.2 10 425 7.0 68.6 75.0
Example B8-6 29.7 11 441 7.1 67.5 73.4
Example B8-7 14.9 11 444 7.2 66.9 72.8
 

[Example B9-1] Investigation of Influence of Electrolyte Solution

      A cell for cathode evaluation was assembled in the same manner as in Example B3-2 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:2, was used instead of the electrolyte solution used in Example B3-2 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).

Example B9-2

      A cell for cathode evaluation was assembled in the same manner as in Example B3-2 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate were mixed at a volume ratio of 1:1:1, was used instead of the electrolyte solution used in Example B3-2 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).

Comparative Example B9-1

      A cell for cathode evaluation was assembled in the same manner as in Comparative Example B3-7 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:2, was used instead of the electrolyte solution used in Comparative Example B3-7 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).

Comparative Example B9-2

      A cell for cathode evaluation was assembled in the same manner as in Comparative Example B3-7 except that a non-aqueous electrolyte solution, in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate were mixed at a volume ratio of 1:1:1, was used instead of the electrolyte solution used in Comparative Example B3-7 (a non-aqueous electrolyte solution in which LiPF 6 was dissolved at a concentration of 1 M in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1:1).
      <Evaluation Results>
      Table 72 shows evaluation results of ionic resistance, reaction resistance, room temperature rate characteristic, and low-temperature discharge characteristic of Example B3-2, Example B9-1, Example B9-2, Comparative Example B3-7, Comparative Example B9-1, and Comparative Example B9-2.
[TABLE-US-00073]
TABLE 72
 
          Room Low-
          temperature temperature
    |Z|ion at |Z|ion at |Z|re at rate discharge
  Dispersant 25° C. −20° C. 25° C. characteristic characteristic
  Type [Ω] [Ω] [Ω] [%] [%]
 
 
Example B3-2 b 10 421 4.9 69.1 76.0
Example B9-1 b 10 416 4.8 69.4 76.4
Example B9-2 b 10 407 4.7 69.9 76.8
Comparative Not used 16 607 10.2 54.4 44.9
Example B3-7            
Comparative Not used 17 601 10.0 55.1 45.5
Example B9-1            
Comparative Not used 17 598 9.8 55.7 45.9
Example B9-2            
 
      From Example B9-1 and Example B9-2, it was confirmed that all characteristics were improved regardless of the type of electrolyte solution, as compared to the comparative example. In addition to the electrolyte solutions shown in the present examples, the same effects are expected to be obtained regardless of the type of non-aqueous electrolyte solution as long as it is a non-aqueous electrolyte solution that is generally used.
      Next, the type of active material was changed, and evaluation was performed in the same manner.

[Examples B10-1 to B10-3] Comparison of Active Material Species

      Using the carbon material dispersion varnish used in Example B3-2, the cell for cathode evaluation was assembled by dispersion performed in the same manner as in Example B3-2 according to the active material and composition shown in Table 73.

Comparative Examples B10-1 to B10-3

      Using the carbon material dispersion varnish used in Comparative Example B3-1, the cell for cathode evaluation was assembled by dispersion performed in the same manner as in Comparative Example B3-1 according to the active material and composition shown in Table 73.
[TABLE-US-00074]
TABLE 73
 
  Composition of cathode mixture paste
  Dispersant Carbon material Binder Active material Solvent
    Content   Content   Content   Content   Content
  Type (%) Type (%) Type (%) Type (%) Type (%)
 
Example B10-1 b 0.04 HS 100 2.0 PVDF 2.0 LCO 54.0 NMP 42.0
Example B10-2 b 0.04 HS 100 2.0 PVDF 2.0 NCA 54.0 NMP 42.0
Example B10-3 b 0.04 HS 100 2.0 PVDF 2.0 LFP 48.0 NMP 48.0
Comparative ba 0.04 HS 100 2.0 PVDF 2.0 LCO 54.0 NMP 42.0
Example B10-1                    
Comparative ba 0.04 HS 100 2.0 PVDF 2.0 NCA 54.0 NMP 42.0
Example B10-2