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1. WO2016116867 - POUDRES DE CATHODE À BASE D'OXYDE DE LITHIUM MÉTALLIQUE POUR DES BATTERIES HAUTE TENSION AU LITHIUM-ION

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

Claims

1. A lithium metal oxide powder for use as a cathode material in a rechargeable battery, comprising a core and a surface layer, the core having a layered crystal structure comprising the elements Li, M and oxygen, wherein M has the formula M = (Niz (Ni½ Mn./2)y Cox)i-k Ak, with 0.15<x≤0.30, 0.20<z≤0.55, x+y+z= l and

0≤k≤0.1, wherein A is a dopant, wherein the Li content is stoichiometrically controlled with a molar ratio 0.95≤Li : M≤1.10; and wherein the surface layer comprises the elements Li, M' and oxygen, wherein M' has the formula M'= (Niz- (Ni½ Mn½)y' Cox-)i-k' Ak-, with x'+y'+z'= l and 0<k'≤0.1, and wherein y7(y'+2z')≥l . l*[y/(y+2z)] and 2x/(y+2z) = 2x'/(y'+2z').

2. The lithium metal oxide powder of claim 1, wherein the core has a radially constant molar ratio x:y:z.

3. The lithium metal oxide powder of claim 1, wherein the surface layer has an outer and an inner interface, the inner interface being in contact with the core, and wherein the concentration of Mn at the outer interface is higher than the concentration at the inner interface.

4. The lithium metal oxide powder of claim 1, wherein the surface layer comprises at least 3 mol% Al, the Al content in the surface layer being determined by XPS.

5. The lithium metal oxide powder of claim 3, wherein the core has an Al content of 0.1-3 mol%, and wherein the surface layer has an Al content that increases from the Al content of the core at the inner interface to at least 10 mol% at the outer interface, the Al content being determined by XPS.

6. The lithium metal oxide powder of claim 1, wherein the surface layer comprises an intimate mixture of elements of the core and nanometric crystalline AI2O3.

7. The lithium metal oxide powder of claim 3, wherein the core has an F content of less than 0.05 mol%, and wherein the surface layer has an F content that increases from less than 0.05 mol% at the inner interface to at least 3 mol% at the outer interface, the F content being determined by XPS.

8. The lithium metal oxide powder of claim 1, wherein A is either one or more of the elements of the group consisting of Al, Ti, Mg, W, Zr, Cr and V.

9. The lithium metal oxide powder of claim 1, wherein the surface layer consists of an intimate mixture of elements of the core, LiF and AI2O3, and either one or more compounds of the group consisting of Ti02, MgO, WO3, Zr02, Cr203 and V2O5.

10. The lithium metal oxide powder of claim 1, wherein 0.15≤x<0.25, 0.20≤z<0.40 and 1 < Li : M < 1.10.

11. The lithium metal oxide powder of claim 1, wherein the F content of the core = 0 mol%.

12. The lithium metal oxide powder of claim 1 wherein the surface layer has a thickness between 50 and 400nm.

13. The lithium metal oxide powder of claim 1, wherein the surface layer has an outer and an inner interface, the inner interface being in contact with the core, and wherein the concentration of Mn at the outer interface is higher than the concentration at the inner interface; wherein the surface layer has an Al content that increases from the Al content of the core at the inner interface to at least 10 mol% at the outer interface; wherein the surface layer has an F content that increases from less than 0.05 mol% at the inner interface to at least 3 mol% at the outer interface, the Al and F content being determined by XPS.

14. The lithium metal oxide powder of claim 13, wherein the molar ratio Mn/AI at the inner interface of the surface layer is smaller than the molar ratio of Mn/AI at the outer interface of the surface layer.

15. A method for making the lithium metal oxide powder of claim 1, comprising the steps of:

- providing a first mixture comprising a lithium M-oxide powder, with

M = (Niz (Ni./2 Mn./2)y Cox)i-k Ak, 0.15≤x<0.30, 0.20≤z<0.55, x+y+z= l and 0≤k<0.1, and a first precursor compound comprising Mn,

- heating the first mixture to a first sintering temperature between 500°C and 700°C, - sintering the first mixture at the first sintering temperature for a first period of time, thereby obtaining the lithium metal oxide powder, and cooling the powder.

16. A method for making the lithium metal oxide powder of claim 4, comprising the steps of:

- providing a first mixture comprising a lithium M-oxide powder, with

M = (Niz (Ni½ Mn./2)y Cox) i-k Ak, 0.15<x≤0.30, 0.20<z≤0.55, x+y+z= l and 0≤k≤0.1, and a first precursor compound comprising Al,

- heating the first mixture to a first sintering temperature between 600°C and 800°C, - sintering the first mixture at the first sintering temperature for a first period of time,

- cooling the first sintered mixture,

- adding a second precursor compound comprising Mn to the first sintered mixture, thereby obtaining a second mixture,

- heating the second mixture to a second sintering temperature between 500 and 700°C,

- sintering the second mixture at the second sintering temperature for a second period of time, thereby obtaining the lithium metal oxide powder, and cooling the powder.

17. A method for making the lithium metal oxide powder of claim 7, comprising the steps of:

- providing a first mixture comprising a lithium M-oxide powder, with

M = (Niz (Ni½ Mn./2)y Cox) i-k Ak, 0.15≤x<0.30, 0.20≤z<0.55, x+y+z= l and 0≤k≤0.1, and a first precursor compound comprising Al,

- heating the first mixture to a first sintering temperature between 600°C and 800°C, - sintering the first mixture at the first sintering temperature for a first period of time,

- cooling the first sintered mixture,

- adding a second precursor compound comprising Mn to the first sintered mixture, thereby obtaining a second mixture,

- heating the second mixture to a second sintering temperature between 500 and 700°C,

- sintering the second mixture at the second sintering temperature for a second period of time, thereby obtaining a second sintered mixture,

- cooling the second sintered mixture,

- adding a fluorine-containing polymer and a third precursor compound comprising Al to the second sintered mixture, thereby obtaining a third mixture,

- heating the third mixture to a third sintering temperature between 250 and 500°C,

- sintering the third mixture at the third sintering temperature for a third period of time, thereby obtaining the lithium metal oxide powder, and cooling the powder.

18. A method for making the lithium metal oxide powder of claim 4, comprising the steps of:

- providing a mixture comprising a lithium M-oxide powder, with

M = (Niz (Ni½ Mn./2)y Cox) i-k Ak, 0.15<x≤0.30, 0.20<z≤0.55, x+y+z= l and 0≤k≤0.1, a first precursor compound comprising Mn and a second precursor compound comprising Al,

- heating the mixture to a sintering temperature between 500°C and 700°C,

- sintering the mixture at the sintering temperature for a period of time, and

- cooling the sintered mixture.

19. The method according to claim 17, wherein the fluorine-containing polymer is either one of a PVDF homopolymer, a PVDF copolymer, a PVDF-HFP polymer (hexa-fluoro propylene) and a PTFE polymer.