Patent ID: 9634327
Date: 2017-04-25
CPC Classifications: C01B,C01P,C04B,H01M,Y02E,Y02P

Claim:
1. A negative electrode active material for a lithium ion secondary battery, comprising silicon, copper and oxygen as major constitutional elements, the negative electrode active material for a lithium ion secondary battery, containing fine particles of silicon having an average crystallite diameter (D x ) measured by an X-ray diffractometry using a half width of the (111) plane of the silicon phase of 50 nm or less, the negative electrode active material having average elemental ratios measured by an enemy dispersive X-ray analysis in a measurement field of 200 μm×200 μm, expressed by molar ratios, Cu/(Si+Cu+O) of from 0.02 to 0.30 and O/(Si+Cu+O) of from 0.02 to 0.30.