▎ 摘　　要

NOVELTY - Core shell structure of nickel cobalt sulfide (NiCo2S4) porous microsphere graphene negative electrode material comprises nickel nitrate, cobalt nitrate, and thiourea grafted graphene with 5-12:10-25:100 mass ratio. USE - Core shell structure of NiCo2S4 porous microsphere graphene negative electrode material used in lithium ion battery. ADVANTAGE - The core shell structure of NiCo2S4 porous microsphere graphene negative electrode material enables to prevent thermal cracking, and has excellent conductivity which forms three-dimensional conductive network. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing core shell structured of NiCo2S4 porous microsphere graphene negative electrode material, which involves: (A) adding graphite, sodium nitrate, and potassium permanganate to concentrated sulfuric acid on ice water bath, stirring at constant speed for low temperature treatment, medium temperature activation, and high temperature oxidation, filtering, centrifuging, washing, and removing impurities by dialysis; dispersing product in solvent of distilled water, placing in constant temperature ultrasonic breaker for ultrasonic peeling, and lyophilizing solid product to prepare graphene with high degree of oxidation; (B) adding graphene with high degree of oxidation to distilled water solvent, adding sodium hydroxide, and chloroacetic acid after uniform ultrasonic dispersion, reacting ultrasonically at 40-80 degrees C for 3-5 hours, centrifuging, washing, removing impurities followed by dialysis, drying to prepare highly carboxylated graphene; (C) adding graphene to sulfuric acid solution with pH 3-5, adding thiourea after uniform ultrasonic dispersion, heating to 80-90 degrees C, reacting for 5-15hours, filtering, washing, dialyzing to remove impurities, and drying to prepared thiourea grafted graphene; (D) adding nickel nitrate, and cobalt nitrate to mixed solvent of distilled water, and glycerol, stirring uniformly, pouring solution into hydrothermal reactor, heating to 160-200 degrees C, reacting for 4-10hours, filtering, washing, and drying to prepare nickel cobalt (NiCo) glycerol salt precursor; (E) adding thiourea grafted graphene, NiCo-glycerate precursor to ethanol solvent, transferring solution in hydrothermal reactor after ultrasonic dispersion is uniform, heating to 160-180 degrees C for 12-24hours, filtering, washing, and drying, placing solid product in resistance furnace with 2-5 degrees C/minute heating rate, increasing temperature to 600-700 degrees C, maintaining temperature; and (F) calcining for 2-3 hours to prepare electrode material.