摘要 |
A lithium-containing silicon oxide powder which is used as a negative electrode material for lithium ion secondary batteries. At least some of the particles that constitute this lithium-containing silicon oxide powder are coated with carbon. This powder is characterized in that, with respect to peaks assigned to Si in the diffraction angle (2&thetas;) range from 47.1° to 47.7° in an X-ray diffraction measurement using a CuKα ray, the peak height (P1) before the lithium-containing silicon oxide powder is mixed with water and the peak height (P2) after the lithium-containing silicon oxide powder is mixed with water and dried satisfy P2/P1 ≥ 0.42. This lithium-containing silicon oxide powder is suppressed in reactivity with water. |