▎ 摘　　要

NOVELTY - A silicon-graphene composite cathode material comprises (in weight%) silicon powder (10-99), graphene (1-90) and amorphous carbon (0-40). The silicon powder has grain size of 20 nm to 5 mu m. The graphene forms three-dimensional solid conductive network with an internal cavity. The silicon powder is coated on the cavity to form spherical or sphere-like composite granules. The grain size of composite granules is 500 nm to 15 mu m. USE - Silicon-graphene composite cathode material is used for lithium ion battery. ADVANTAGE - The lithium ion battery using the composite cathode material has high capacity, excellent cyclic performance under the current density of 200 mA/g, and capacity-retaining rate of 98%, and is prepared at high yield by simple process. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of silicon-graphene composite cathode material, which involves dispersing silicon powder, graphene oxide, amorphous carbon in solvent, uniformly stirring, spray drying at 120-220 degrees C (inlet temperature) and 80-140 degrees C (outlet temperature) to remove solvent, heating at 500-1100 degrees C, introducing protective gas, cracking gaseous, liquid or solid carbon source into amorphous carbon, performing high-temperature annealing for 1-24 hours, reducing graphene oxide, naturally cooling to room temperature to obtain silicon-graphene composite cathode material. The content of silicon powder and graphene is 1 part weight and 0.017-15 parts weight, respectively, when the content of amorphous carbon is 0. The content of silicon powder and graphene is 1 part weight and 0.01-9 parts weight, when the content of amorphous carbon is 0-40 weight%.