▎ 摘　　要

NOVELTY - Preparation of cathode composite material, involves (1) dissolving the carbon source in an organic solvent, adding organosilicon to it after being completely dissolved, and stirring for 3-5 hours, mixing the carbon source solution and the organic silicon thoroughly, then heating and stirring to remove the organic solvent, and then drying, (2) under the protection of inert gas, cracking the product obtained in step (1) at a high temperature at 900-1500degrees Celsius to obtain silicon-metal-carbon composite material, (3) mixing and stirring the silicon-metal-carbon composite material and the graphene slurry to obtain a mixed slurry, and (4) spray drying and granulating the mixed slurry. The mass ratio of the carbon source to the organic silicon is 1:2-2:1. The mass ratio of silicon-metal-carbon composite material to graphene is 4:1-99:1. USE - Preparation of composite material (claimed) for cathode used in electrochemical device e.g. lithium ion battery used in electric automobile and mobile electronic device. ADVANTAGE - The obtained cathode composite material has lower expansibility, improved conductivity and good cycle performance. DETAILED DESCRIPTION - Preparation of cathode composite material, involves (1) dissolving the carbon source in an organic solvent, adding organosilicon to it after being completely dissolved, and stirring for 3-5 hours, mixing the carbon source solution and the organic silicon thoroughly, then heating and stirring to remove the organic solvent, and then drying, (2) under the protection of inert gas, cracking the product obtained in step (1) at a high temperature at 900-1500degrees Celsius to obtain silicon-metal-carbon (Si-M-C, where M includes at least one of boron, nitrogen or oxygen) composite material, (3) mixing and stirring the Si-M-C composite material and the graphene slurry to obtain a mixed slurry, and (4) spray drying and granulating the mixed slurry. The mass ratio of the carbon source to the organic silicon is 1:2-2:1. The mass ratio of silicon-metal-carbon composite material to graphene is 4:1-99:1.