▎ 摘　　要

NOVELTY - A silicon-oxygen material comprises silicon oxide (I), and is in the form of primary particles having Wadell sphericity of more than 0.92. USE - Silicon-oxygen material is used for preparing material for forming negative electrode used for lithium ion battery (all claimed). ADVANTAGE - The silicon-oxygen material has high sphericity, and has a stable structure during cycle process, can avoid the problem of the breaking of material particles caused by repeated generation of solid electrolyte interface films. The negative electrode formed using the silicon-oxygen material provides lithium ion battery having improved cycle performance and reduced volume expansion caused by the generation of the solid electrolyte interface films. DETAILED DESCRIPTION - A silicon-oxygen material comprises silicon oxide of formula: SiOx(I), where x is more than 0 to less than 2, and is in the form of primary particles having Wadell sphericity of more than 0.92. INDEPENDENT CLAIMS are included for the following: a negative electrode material, which comprises the silicon-oxygen material; and preparation of the negative electrode material, which involves heat-treating raw materials for preparing silicon-oxygen materials and cooling to obtain silicon-oxygen material containing silicon oxide.