▎ 摘　　要

NOVELTY - Preparing silicon (Si)/iron (Fe)/iron oxide (Fe3O4)/carbon (C) (Si/Fe/Fe3O4/C) composite material by using supercritical carbon dioxide (CO2) fluid medium involves adding silicon powder, carbon material and iron source into the ball mill jar, then wet grinding agent and ball mill beads is added, sealed and the ball mill jar is vacuumized, the CO2 gas is pumped into the sealed ball milling tank, and the ball milling reaction is carried out under supercritical conditions to obtain the Si/ iron carbonate (FeCO3)/C precursor product, after the ball milling reaction is finished, the solid product in the ball milling tank is collected and dried to obtain powder, sintering the collected powder under the inert atmosphere to obtain the Si/Fe/Fe3O4/C composite material. USE - Method for preparing Si/Fe/Fe3O4/C composite material by using supercritical CO2 fluid medium used as the cathode material of lithium-ion battery (claimed). ADVANTAGE - The method has simple process, economical and environmental protection, easy industrialization and the prepared Si/Fe/Fe3O4/C composite material has excellent rate performance and cycle stability, and can be widely used in high-performance lithium-ion batteries and other fields as a negative electrode material. DESCRIPTION OF DRAWING(S) - The drawing shows an X-ray diffraction pattern of Si/FeCO3/C precursor and Si/Fe/Fe3O4/C composite material prepared.