▎ 摘　　要

NOVELTY - A lithium battery composite negative electrode material comprises silicon dioxide, lithium hydroxide and Tween-80(RTM: polyoxyethylene (20) sorbitan monooleate) are sintered at high temperature to prepare silicon-carbon negative electrode material, and carbon microsphere is modified to prepare carbon negative electrode material, conductive agent and binder. USE - Lithium battery composite negative electrode material. ADVANTAGE - The composite negative electrode material has large specific capacity, high initial charging efficiency, excellent safety and cycle life. The method overcomes the low capacity of the carbon negative electrode, at the same time effectively avoids the volume expansion effect of silicon in the charging and discharging process, and carbon material can improve the conductivity of the silicon, improve the electrical contact between the electrode active substance and current collector, and improve the circulation stability of the silicon. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of lithium battery composite negative electrode material, which involves (s1) preparing the silicon-carbon negative electrode material, (s1.1) placing silicon dioxide, lithium hydroxide, Tween 80 (RTM: polyoxyethylene (20) sorbitan monooleate) in a mass ratio of (40-80):(20-40):1 in ball mill, ball-milling, and filtering by vibration sieve, (s1.2) placing the ball-milled raw material into ball mill stirrer, stirring, adding ethanol in a mass ratio of 1:10-1:15 to the raw material, and stirring uniformly to obtain slurry, and (s1.3) placing in high temperature sintering furnace, heating at 550-750℃ at the speed of 2-8℃/minute for 6-10 hours, and cooling to obtain silicon carbon material negative electrode, (s2) preparing the carbon negative electrode material, (s2.1) adding the carbon microsphere into mixed solution of concentrated sulfuric acid and concentrated nitric acid, heating to reflux for 1-3 hours, filtering and washing with distilled water until neutral, and vacuum-drying at 40℃, and (s2.2) placing the acid-treated carbon microsphere and γ-methacryloxypropyltrimethoxysilane into deionized water, stirring at 45-55℃ for 12 hours, washing by distilled water, and vacuum-drying at 40℃ to obtain carbon negative electrode, and (s3) adding conductive agent and binder to the silicon-carbon negative electrode material and carbon negative electrode material.