▎ 摘　　要

NOVELTY - Silicon-carbon composite material, comprises silicon graphene composite framework with hollow spherical porous structure and at least a graphene layer coated on inner and outer surfaces of the silicon graphene compound framework. USE - Silicon-carbon composite material for negative electrode of sheet secondary battery used in new energy automobile. ADVANTAGE - The silicon-carbon composite material has excellent conductivity, high specific characteristics, high energy density, high cycle performance, and long service life, and can effectively reduce the damage of the pole piece powder-off and the SEI film caused by the silicon volume expansion in the charging and discharging process. The graphene layer coated on the inner and outer surfaces of the silicon graphene composite framework reserves space for the volume expansion of silicon, and the graphene coating has better conductivity which can better improve the conductivity of the material, when it is applied to the negative electrode material, can reduce or even save the dosage of the conductive agent. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) preparation method of silicon-carbon composite material, involves mixing layered silicate mineral and solution of cationic surfactant, and separating to obtain composite silicon source precursor of cationic surfactant intercalation; and mixing composite silicon source precursor with metal aluminum catalyst in inert atmosphere, carrying out thermal reduction treatment, and carrying out acid washing to obtain silicon-carbon composite material, where silicon-carbon composite material is hollow spherical porous structure of which at least inner surface and outer surface are coated with graphene. (2) negative electrode of sheet; (3) secondary battery. DESCRIPTION OF DRAWING(S) - The drawing shows a structure schematic diagram of the silicon-carbon composite material. 1Invention silicon graphene composite framework 2Alternately laminated graphene layer 3Comparative example 4Comparative example 5Silicon graphene composite particles