▎ 摘　　要

NOVELTY - Silicon-carbon composite material comprises a three-core structure coated with three-layer carbon shell on the surface of the nano-silica. The core of the silicon carbon cathode material is nano-silicon particles. The surface of the nano-silicon particles is sequentially coated with a hard carbon layer, a graphene layer and a soft carbon layer. The hard carbon layer is formed by pyrolyzing sweet potato starch and the surface is provided with a loose porous structure. The soft carbon layer is formed by mixing asphalt and artificial graphite and carbonizing. USE - Silicon-carbon composite material for lithium ion battery. ADVANTAGE - The silicon-carbon composite material has low specific surface area, high tap density and so on on the materialization index, high charge and discharge coulomb efficiency, high, gram volume cycle performance and excellent multiplying power performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a preparation method of silicon-carbon composite material.