▎ 摘　　要

NOVELTY - Cathode active material comprises inner layer material and covering the outer layer material. The inner layer material includes multi-layer graphene and silicon particles. The multi-layer graphene is set with multiple overlapped sheets. The gap between adjacent sheets is 20-500 nm. The silicon particle is located between the layers of the multilayer graphene. The outer layer material is carbon layer. USE - The cathode active material is useful in lithium-ion battery. ADVANTAGE - The cathode active material: has high electrical conductivity, high content, low expansion, circulation performance and high rate performance. DETAILED DESCRIPTION - INDEPENDENT CLAIM is also included for: preparing cathode active material comprising (S1) dispersion liquid containing silicon particle and dispersing solvent, (S2) mixing multi-layer graphene and dispersion liquid, carrying out ultrasonic plugging layer treatment, filtering, drying to obtain the first precursor, carrying out heating treatment under reduction in non-oxidizing atmosphere, cooling to obtain the second precursor, (S3) carrying out mechanical modification of the second precursor to obtain the inner layer material, where the inner layer material comprising multi-layer graphene and silicone granule, where the multi-layer graphene is set with multiple overlapped sheets, where the gap between adjacent sheets is 20-500 nm, (S4) formation of carbon layer on the inner layer material surface; and #a lithium-ion battery comprising a battery shell, The battery is arranged inside the battery shell and the electrolyte in the battery shell is filled. The electric core comprises orderly set with the positive pole piece, diaphragm and negative pole piece. The cathode pole piece comprises a cathode current collector and a cathode material which is set on cathode current collector.