▎ 摘　　要

NOVELTY - Manufacturing silicon-carbon-graphene composite from silicon sludge involves processing colloidal solution containing silicone sludge and mixing water-soluble carbon precursor and graphene oxide under ultrasonic conditions. The mixture is heat-treated and then dried to obtain silicon-carbon precursor-graphene oxide composite. The colloidal solution is sprayed on silicon carbide particle. The upper portion of the colloidal solution, carbon precursor and graphene oxide are mixed with silicon carbide particle to obtain silicon-carbon-graphene composite having the core-shell structure. USE - Method for manufacturing silicon-carbon-graphene composite from silicon sludge used for manufacturing secondary battery cathode material (claimed). ADVANTAGE - The method enables to manufacture silicon-carbon-graphene composite from silicon sludge that has maximum capacity of 372 milliAmpere-hour/g, high charging and discharging capacity and excellent cycleability. DETAILED DESCRIPTION - Manufacturing silicon-carbon-graphene composite from silicon sludge involves processing colloidal solution containing silicone sludge and mixing water-soluble carbon precursor and graphene oxide under ultrasonic conditions. The mixture is heat-treated and then dried to obtain silicon-carbon precursor-graphene oxide composite. The colloidal solution is sprayed on silicon carbide particle. The upper portion of the colloidal solution, carbon precursor and graphene oxide are mixed with silicon carbide particle to obtain silicon-carbon-graphene composite having the core-shell structure, where silicon particles surround graphene shell coated with carbon. The thickness of the carbon coating is 2-5nm and thickness of graphene shell is 3-15nm.