▎ 摘　　要

NOVELTY - Preparation of carbon-silicon-nitrogen oxide-silicon composite negative electrode material involves (i) putting silicon nitride and silicon dioxide in proportion to the ball mill jar, adding dispersion medium, taking out the slurry and putting in an oven, and drying to obtain silicon nitride doped silicon dioxide composite powder, (ii) putting the silicon nitride doped silicon dioxide composite powder in a high-temperature furnace, and heating to obtain silicon tetranitride doped silicon nitride composite powder, (iii) mixing silicon tetranitride doped silicon nitrogen oxide composite powder and carbon source evenly, heating to obtain silicon tetranitride doped silicon nitrogen oxide doped carbon composite powder, and (iv) preparing silicon doped silicon nitrogen oxide doped carbon composite material by putting the carbon-silicon dinitride-silicon composite powder into a vacuum furnace, heating, and decomposing silicon tetranitride to form dispersed porous nano-silicon particles. USE - Preparation of carbon-silicon-nitrogen oxide-silicon composite negative electrode material used in lithium-ion batteries. ADVANTAGE - The method provides negative electrode material with excellent electrochemical performance. DETAILED DESCRIPTION - Preparation of carbon-silicon-nitrogen oxide-silicon composite negative electrode material involves (i) preparing silicon nitride doped silicon dioxide composite powder by putting silicon nitride and silicon dioxide in proportion to the ball mill jar, adding dispersion medium, taking out the slurry and putting in an oven, after processing at 200-500 rpm for 1-24 hours, and drying at 80-150℃ for 10-24 hours to obtain silicon nitride doped silicon dioxide composite powder, (ii) preparing silicon tetranitride doped silicon nitride composite powder by putting the silicon nitride doped silicon dioxide composite powder in a high-temperature furnace, and heat-treating at 800-1400℃ for 1-20 hours under nitrogen atmosphere to obtain silicon tetranitride doped silicon nitride composite powder, (iii) preparing silicon tetranitride doped silicon nitrogen oxide doped carbon by mixing silicon tetranitride doped silicon nitrogen oxide composite powder and carbon source evenly, heating at 500-1000℃ for 1-20 hours under protective atmosphere, so that the carbon source decomposes, forming a uniform carbon coating layer on the surface of silicon tetranitride doped silicon nitrogen oxide composite powder to obtain silicon tetranitride doped silicon nitrogen oxide doped carbon composite powder, and (iv) preparing silicon doped silicon nitrogen oxide doped carbon composite material by putting the carbon-silicon dinitride-silicon composite powder into a vacuum furnace, heat-treating at 800-1500℃ for 0.5-10 hours under a vacuum degree of 10-4-100 Pa, and decomposing silicon tetranitride to form dispersed porous nano-silicon particles. The particle size of silicon tetranitride is 50 nm-10 μm. The silicon dioxide is more than one of nano-silicon dioxide, silica, quartz, silicon micropowder, and silica sol, with a particle size of 10-100 nm. The dispersion medium is more than one of absolute ethanol, N-methylpyrrolidone, and deionized water. The mass ratio of silicon tetranitride, silicon dioxide, and dispersion medium is 1: 0.01-0.4: 1-3. The mass ratio of silicon tetranitride doped silicon nitrogen oxide composite powder to carbon source is 1:0.5-3. The carbon source comprises organic carbon source and inorganic carbon source, where the organic carbon source is more than one of resin, pitch, starch, glucose, dextrin, sucrose, citric acid, polythiophene, polypyrrole and polyaniline, and the inorganic carbon source is one of acetylene black, carbon black, carbon nanotubes, carbon fibers or graphene. The mass ratio of organic carbon source and inorganic carbon source in carbon source is 1: 0.1-1. The protective atmosphere is more than one of nitrogen, argon, methane, ethane, ethylene, acetylene or hydrogen.