▎ 摘　　要

NOVELTY - Preparation of graphene coated silicon cathode material involves preparing graphene oxide suspension by adding concentrated sulfuric acid into concentrated phosphoric acid, adding graphite and potassium permanganate powders, pouring into mixture of ice-water and hydrogen peroxide and ultrasonic dispersing in deionized water; preparing nanosilica suspension by adding concentrated sulfuric acid into hydrogen peroxide, adding silica nanoparticles, ultrasonic dispersing in absolute ethanol, and ultrasonic dispersing in deionized water; and mixing graphene oxide and nanosilica suspensions. USE - Method for preparing graphene coated silicon cathode material (claimed). ADVANTAGE - The method is simple and easy to control, uses raw materials with wide sources and low price, and has strong operability. The material has 0.01-1.2 V circulation performance, 200 mA/g electric current density, 2746 mAh/g discharge circuit, and 100 times circulation discharge circuit capacity. DETAILED DESCRIPTION - Preparation of graphene coated silicon cathode material comprises: (A) preparing graphene oxide suspension by adding concentrated sulfuric acid into concentrated phosphoric acid under ice water bath conditions, stirring, adding graphite, stirring, slowly adding potassium permanganate powders, stirring for 30-60 minutes, heating to 45-55 degrees C, stirring for 20-28 hours, reacting, cooling to room temperature, slowly pouring into mixture of ice-water and hydrogen peroxide, centrifuging, washing with dilute hydrochloric acid, washing with deionized water to pH of 6.8-7.2, vacuum drying at 45-55 degrees C to get graphite oxide, and ultrasonic dispersing in deionized water; (B) preparing nanosilica suspension by adding concentrated sulfuric acid into hydrogen peroxide under ice-cooling conditions, stirring, adding silica nanoparticles, stirring, centrifuging, washing and drying, ultrasonic dispersing in absolute ethanol, heating in water bath, slowly dropping coupling agent, heating while stirring for 8-16 hours, cooling, suction filtering, drying, and ultrasonic dispersing in deionized water; and (C) mixing prepared graphene oxide suspension and nanosilica suspension, stirring, centrifuging, washing, and high temperature heating under protective atmosphere.