▎ 摘　　要

NOVELTY - A composite material comprises tin dioxide, nickel ferrite and graphene. The content of tin dioxide is 10-70 wt.% with respect to content of composite material. The content of graphene is 25-30 wt.% with respect to content of composite material. USE - Composite material is used in preparation of negative electrode (claimed). ADVANTAGE - The composite material has excellent stability. By adjusting content rate of tin dioxide, the lithium storage performance of the composite material is improved. The negative electrode obtained using the composite material has current density of 0.2 A.g-1, specific capacity of 500-700 mAh.g-1 after 50 cycles, and initial discharge capacity of 50-80%. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of composite material, which involves mixing ferric nitrate heptahydrate and nickel nitrate hexahydrate in deionized water, adding ethylene glycol solution of stannous chloride, stirring, adding aqueous graphite oxide solution, mixing uniformly, adding urea to the resultant mixed solution, stirring, performing hydrothermal reaction, cooling the resultant mixture, centrifuging, washing, and drying; and (2) usage method of composite material in preparation of negative electrode, which involves mixing the composite material, electroconductive carbon black and polyvinylidene fluoride in mass ratio of 8:1:1, coating the resultant mixture on a copper foil, drying and obtaining negative electrode.