▎ 摘　　要

NOVELTY - Preparation of high thermal conductivity graphene film, involves adding concentrated sulfuric acid and sodium nitrate in beaker, cooling, adding natural graphite, mixing, adding potassium permanganate and deionized water, reacting, adding reaction solution into deionized water, adding hydrogen peroxide, observing solution, terminating reaction, filtering, washing, ultrasonic peeling, obtaining suspended graphene oxide (GO) solution, coating resulting suspension on glass plate, drying film, obtaining GO film, cutting into square, sandwiching, applying pressure, heat-treating and cooling. USE - Preparation of high thermal conductivity graphene film (claimed). ADVANTAGE - The preparation process adopts improved Hummers method to prepare graphene oxide. High thermal conductivity graphene film is prepared by carbonization treatment. High thermal conductivity graphene film is effectively restored by heat treatment at 250 degrees C. The graphene film obtained by carbonization treatment at 900 degrees C has graphite-like structure. Thermal conductivity of graphene film reaches 540 W/(m.K) in the plane direction. DETAILED DESCRIPTION - Preparation of high thermal conductivity graphene film, involves drying natural graphite at 60 degrees C for 12 hours, adding 115 mL concentrated sulfuric acid and 2.5 g sodium nitrate in dry beaker of 98%, cooling under ice-cooling condition at temperature of below 5 degrees C, adding 5 g natural graphite to beaker under stirring condition, mixing well, adding 15 g potassium permanganate for three times within 1 hour, placing beaker in constant temperature water bath of 45 degrees C, carrying out thermal insulation for 0.5 hours, adding 230 mL deionized water in dropwise manner, carrying out thermal insulation reaction for 0.5 hours when system temperature is 45 degrees C, controlling temperature of reaction solution which does not exceed 70 degrees C, adding reaction solution into 600 mL deionized water, adding 25 mL hydrogen peroxide, observing solution whose color is changed from brick red to bright yellow, terminating of reaction, carrying out thermal filtration, washing with 2 L dilute hydrochloric acid and plenty of deionized water until pH value of filtrate reaches 7, carrying out ultrasonic peeling for 1.5 hours with ultrasonic cell pulverizer of 500 W/h, obtaining stably suspended graphene oxide (GO) solution, uniformly coating of resulting suspension on glass plate to make directional flow of GO suspension, drying film in vacuum oven at 60 degrees C, obtaining GO film, cutting GO film into square, sandwiching between two smooth graphite sheets, applying pressure, carrying out heat treatment in nitrogen atmosphere for 30 minutes at 250 degrees C and cooling to room temperature in nitrogen atmosphere.