▎ 摘　　要

NOVELTY - Method for preparing a nitrogen-doped modified silicon/graphite/graphene composite material, involves (a) ultrasonically dispersing the nano silicon powder in deionized water, adding the polydiene dimethyl ammonium chloride solution, (b) transferring the ultrasonic solution to a centrifuge tube, discarding the supernatant, re-adding deionized water, ultrasonically dispersing, adding deionized water for cleaning, (c) vacuum drying, (d) taking the prepared modified nano silicon powder and dispersing in alcohol, adding natural graphite, (e) transferring the obtained mixed solution to ball milling tank for ball milling and drying, (f) weighing graphene oxide, urea and ascorbic acid, ultrasonically dispersing in deionized water, (g) adding the modified nano silicon/graphite composite material to the viscous solution, (h) transferring the uniform viscous solution to a water bath, and heating (i) cooling, washing with deionized water and freeze-drying, and (j) calcinating. USE - The method is used for preparing a nitrogen-doped modified silicon/graphite/graphene composite material. ADVANTAGE - The method increases the electrostatic repulsion of nano silicon, improves dispersion performance, prevents local agglomeration, and has excellent electrochemical performance. DETAILED DESCRIPTION - Method for preparing a nitrogen-doped modified silicon/graphite/graphene composite material, involves (a) stirring and ultrasonically dispersing the nano silicon powder in deionized water, adding the polydiene dimethyl ammonium chloride solution under stirring after dispersion, and ultrasonically stirring thoroughly, (b) transferring the ultrasonic solution to a centrifuge tube, discarding the supernatant after centrifugation, re-adding deionized water, ultrasonically dispersing for 5-10 minutes, continuing centrifugation, adding deionized water for cleaning 3-5 times to obtain brown sediment, (c) vacuum drying the obtained brown precipitate to obtain modified nano silicon powder, (d) taking the prepared modified nano silicon powder by ultrasonic for 1-2 hours and dispersing in 15 ml alcohol, adding natural graphite to obtain a mixed solution, (e) transferring the obtained mixed solution to a 100 ml ball milling tank for ball milling, and after ball milling for 3-5 hours, drying to obtain a modified nano-silicon/graphite composite material, (f) weighing graphene oxide, urea and ascorbic acid, ultrasonically dispersing in deionized water, and heating the water bath until the solution becomes viscous, (g) adding the modified nano silicon/graphite composite material to the viscous solution, and performing strong magnetic stirring until a uniform viscous solution is obtained, (h) transferring the uniform viscous solution to a water bath, and heating the water bath to form a columnar colloid, (i) after the water bath heating reaction is completed, cooling to room temperature to obtain a dark brown hydrogel, washing with deionized water and freeze-drying to obtain a dark brown columnar aerogel, and (j) putting the dark brown columnar aerogel in a quartz boat and calcinating.