Search International and National Patent Collections
|1. (WO2013157620) NEGATIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY AND LITHIUM ION SECONDARY BATTERY|
|Title:||NEGATIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY AND LITHIUM ION SECONDARY BATTERY|
Conventionally, the volume of a negative electrode active material changes during a charge-discharge cycle and the conductive network inside the negative electrode gradually degrades. As a result, there is a problem that the capacity of the negative electrode decreases. To address the problem, the purpose of the present invention is to minimize the decrease in the capacity of a negative electrode and to extend the life of a lithium ion secondary battery. A negative electrode active material for lithium ion secondary battery is characterized by including a graphite nuclear material and a covering layer for covering the surface of the nuclear material wherein the thickness of said covering layer is 1 to 200 nm and the bulk modulus of said covering layer is smaller than the bulk modulus of said nuclear material.