▎ 摘　　要

NOVELTY - Active material comprises carbon filament and silicon oxide compound (I), where the content of carbon filament is 10-30 %mass, and the particle size of silicon oxide compound (I) is 10 nm to 10 mu m. USE - The active material is used for negative electrode material of lithium ion battery (claimed). ADVANTAGE - The method grows carbon filament on the surface of silicon oxide to improve the cycle stability of silicon oxide, and suppresses the volume change of silicon oxide in the process of lithium insertion and delithiation to provide high cycle stability, first coulombic efficiency and conductivity. DETAILED DESCRIPTION - Active material comprises carbon filament and silicon oxide compound of formula (I): SiOx, where the content of carbon filament is 10-30 %mass, and the particle size of silicon oxide compound (I) is 10 nm to 10 mu m. x = 0-2. INDEPENDENT CLAIMS are included for the following: (1) a method for preparing the active material, involving performing high-energy ball milling of silicon oxide in an argon atmosphere for 10-30 hours to obtain a precursor, putting the precursor in a chemical vapor deposition device, evacuating to less than or equal to 1x 10-2 Torr, ventilating argon to normal pressure, starting to heat up, passing protective gas 100-500 sccm and reducing gas 20-100 sccm during the heating process, maintaining the temperature at 1000-1200 degrees C for 1-3 hours, and then when it drops to 900-1100 degrees C, introducing the carbon source gas for 10-100 sccm when the temperature drops to 900-1100 degrees C, maintaining the temperature at 900-1000 degrees C for 1-3 hours, turning off the carbon source gas, and naturally cooling the carbon source gas to room temperature to obtain the product; and (2) a use of the active material for negative electrode material of lithium ion battery.