Si-BASED ALLOY NEGATIVE ELECTRODE MATERIAL

摘要

Provided is an Si-based alloy negative electrode material for electricity storage devices such as lithium ion secondary batteries and hybrid capacitors wherein lithium ions move during the charging and discharging of the devices, said Si-based alloy negative electrode material having excellent electrical conductivity. This Si-based alloy negative electrode material is characterized by being a powder that is formed of a composite phase of an Si phase and an SixCuy phase that is composed of an SixCuy alloy which is an intermetallic compound of Si and Cu. This Si-based alloy negative electrode material is also characterized in that the composition of the SixCuy phase satisfies x xCuy phase has an average hardness of 800 HV or less.