| 摘要 |
Provided is a negative-electrode material powder for lithium-ion secondary battery including a silicon-rich layer on the surface of a lower silicon oxide powder, and a negative-electrode material powder for said battery comprising a silicon oxide powder, characterized by satisfying c/d<1, where c is the molar ratio of oxygen to silicon on the surface of the silicon oxide powder and d is that for the entire part thereof. It preferably satisfies one of c<1 and 0.8<d<1.0. Preferably, the surface of the powder is devoid of crystalline silicon, the inside of the powder is amorphous, and the surface includes a conductive carbon film. The surface of said negative-electrode material powder is coated with silicon using disproportionation of SiCl x (X<4). This provides a negative-electrode material powder that can be used as a lithium-ion secondary battery having a large reversible capacity, while a small irreversible capacity, and a method for producing the same. |
