POWDER FOR LITHIUM ION SECONDARY BATTERY NEGATIVE ELECTRODE MATERIAL, LITHIUM ION SECONDARY BATTERY NEGATIVE ELECTRODE AND CAPACITOR NEGATIVE ELECTRODE, AND LITHIUM ION SECONDARY BATTERY AND CAPACITOR

摘要

A negative electrode material powder for a lithium ion secondary battery having a conductive carbon film on the surface of a lower-silicon-oxide powder; wherein a specific surface area in BET measurement ranges from more than 0.3 m 2 /g to 40 m 2 /g, and no SiC peak appears at 2¸= 35.6°±0.01° or the half-value width of the appeared peak is 2° or more in XRD measurement using CuK ± rays. The proportion of said carbon film preferably ranges from 0.2% to 2.5% by mass. Said powder preferably has 100000 ©cm or less of specific resistance. In XRD, P2/P1 < 0.01 is preferably satisfied between the highest value P1 of halo of SiO x and a value P2 of the strongest linear peak of Si (111) above the halo. Accordingly, said powder can be used in the secondary battery with a large discharge capacity and a preferable cycle characteristics for practical use.