▎ 摘　　要

NOVELTY - The application method of graphene/silicon carbon composite material for lithium ion battery, using microcrystalline graphite as carbon source, involves depositing copper foil on graphene/silicon carbon composite material and punching into pole using punch, providing argon-filled glove box, taking lithium sheet as counter electrode, membrane as polypropylene microporous membrane and electrolyte composed of lithium hexafluorophosphate, dimethyl carbonate and ethylene carbonate and assembling into battery. The deposition of copper foil is carried out by mixing purified microcrystalline graphite powder with graphene oxide dispersion to obtain mixed solution, adding dispersing agent, ultrasonically atomizing, forming mixed mist bead, carrying out vapor deposition, heating, adding benzene and trimethylchlorosilane, ultrasonically atomizing, vapor depositing, cooling to room temperature to obtain graphene/silicon carbon composite material on the surface of the copper foil. USE - Application method of graphene/silicon carbon composite material for lithium ion battery. ADVANTAGE - The method provides lithium ion battery with large reversible capacity, design capacity, excellent cycle performance, high current discharge capability and high tap density. DETAILED DESCRIPTION - Application method of graphene/silicon carbon composite material for lithium ion battery, involves using microcrystalline graphite as carbon source, involves depositing copper foil on a graphene/silicon carbon composite material and punching into pole using punch, providing argon-filled glove box, taking lithium sheet as counter electrode, membrane as polypropylene microporous membrane and electrolyte composed of 1 mol/L lithium hexafluorophosphate, dimethyl carbonate and ethylene carbonate and assembling into battery. The volume ratio of dimethyl carbonate and ethylene carbonate is 1:1. The deposition of copper foil on graphene/silicon carbon composite material is carried out by (S1) mixing purified microcrystalline graphite powder with carbon content of not less than 99% with 1-10 mg/mL graphene oxide dispersion in a volume ratio of 1:1-2 to obtain mixed solution, (S2) adding dispersing agent to mixed solution, ultrasonically dispersing to form suspension, transferring to three-necked flask, placing on an ultrasonic nebulizer for ultrasonic atomization at frequency of 20000 Hz for 30 minutes, forming mixed mist bead, (S3) sealing one port of three-necked flask with rubber stopper, connecting one port to inert gas, and connecting another port to tube furnace, carrying out vapor deposition of mixed mist beads on a copper foil substrate placed horizontally in a tube furnace under protection of an inert gas at 400 degrees C for 1 hour, (S4) heating the tube furnace to 800 degrees C at 5 degrees C/minute, opening the three-necked rubber stopper, adding mixed solution of 50% concentration of benzene and 50% concentration of trimethylchlorosilane, plugging the rubber stopper, switching on the ultrasonic nebulizer, ultrasonically atomizing at a frequency of 20000 Hz, switching off the ultrasonic nebulizer, after the mixed mist beads are completely passed into the tube furnace, vapor depositing the mixed mist beads in a tube furnace, taking out and cooling to room temperature for 6 hours to obtain graphene/silicon carbon composite material on the surface of the copper foil. In step (S3) and step (S4), the inert gas flow in the three-necked flask is controlled at 500 mL/minute. The microcrystalline graphite is obtained by purifying microcrystalline graphite. The size of purified microcrystalline graphite powder is 0.5-5 mu m.