SILICON OXIDE, MAKING METHOD, NEGATIVE ELECTRODE, LITHIUM ION SECONDARY BATTERY, AND ELECTROCHEMICAL CAPACITOR.

Particulate silicon oxide having a Cu content of 100-20,000 ppm, an Fe content of 20-1,000 ppm, an Al content of up to 1,000 ppm, an average particle size of 0.1-30 µm, and a BET specific surface area of 0.5-30 m 2 /g is used as negative electrode material in constructing a nonaqueous electrolyte secondary battery. The secondary battery is improved in cycle performance while maintaining the high battery capacity and low volume expansion of silicon oxide.