▎ 摘　　要

NOVELTY - Composite material comprises a secondary particle and a carbon coating layer, the secondary particle comprises the primary particle and conductive carbon material, the primary particle is silicon oxide tail powder doped with metal particles, and the particle diameter of the silicon oxide tail powder is less than 1 micron. USE - Composite material (claimed). ADVANTAGE - The material has improved the comprehensive utilization value of the silicon oxide, and has reduced the cost, has dramatically improved the conductive performance of the secondary particle. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: 1. a method for preparing a composite material, which involves a. placing the silicon oxide tail powder and metal particles in the vacuum heating device, after vacuuming and heating doping to obtain primary particles; b. mixing and granulating the primary particles and the conductive carbon material, forming secondary particles; and c. obtaining the secondary particles for the carbon surface to the composite material; and 2. a kind of lithium-ion battery negative electrode.