▎ 摘　　要

NOVELTY - A highly thermally conductive graphene thick film has thickness of greater than 50 mu m, porosity of 5-40%, and thermal conductivity of 1000-2000 W/mK. The graphene sheet has graphene density of 50-500 mm/mm2. The defects of the graphene sheet are small. The graphene sheet has ID/TG ratio of less than 0.02. The spacing of any two adjacent graphene sheets is less than 20 nm. USE - Highly thermally conductive graphene thick film used in high frequency and high heat flow density device. ADVANTAGE - The highly thermally conductive graphene thick film has thickness of greater than 50 mu m, and thermal conductivity of 1000-2000 W/mK. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of highly thermally conductive graphene film, which involves (i) preparing graphene oxide having an average size of more than 50 mu m into 1-20 mg/ml aqueous graphene oxide solution, making into film, and naturally drying to obtain graphene oxide film, (ii) combining multiple graphene oxide films, uniformly spraying spray liquid on the graphene oxide film surface, swelling the surface, and bonding multiple graphene oxide films together in the thickness direction, (iii) placing the bonded graphene composite film in an oven at not more than 40 degrees C, (iv) placing the dried graphene composite film in a hot press chamber of a hot press, heating at 200 degrees C at a rate of 0.1-5 degrees C/minute, repeatedly hot pressing at 20 MPa for 8-10 times, maintaining for 1 hour, gradually releasing the pressure to 0 MPa, vacuumizing the vacuum suction chamber to -100-10 kPa for 5 minutes, heating at 300 degrees C at a rate of 0.1-5 degrees C/minute, heat preserving for 0.5 hour, hot pressing, repeatedly hot pressing at 60 MPa for 4-6 times, maintaining for 1 hour, gradually releasing the pressure to 0 MPa, vacuumizing the vacuum suction chamber to -100-10 kPa, and naturally cooling, (v) heating the graphene oxide film in an inert gas atmosphere at 1800-3000 degrees C at a rate of 1-20 degrees C/minute, heat preserving at 10-60 MPa for 0.5-8 hours, and cooling.