▎ 摘　　要

NOVELTY - Graphene film with ultrahigh flexibility and high thermal conductivity, is claimed. The density of the high flexible graphene film is 1.93-2.11 g/cm3, the average size of planar orientation of the graphene sheet is more than 100 mu m and conjugated on mutual lap joint. The graphene structure contains 1-4 graphene sheet layers and defect of graphene sheet pole ID/TG is less than 0.01. USE - Used as graphene film with ultrahigh flexibility and high thermal conductivity. ADVANTAGE - The graphene film can be bent repeatedly more than 1,200 times, has elongation at break of 12%-18%, electrical conductivity of 8000-10600 S/cm, and thermal conductivity of 1800-2600 W/mK. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the graphene film, comprising (i) taking average size of more than 100 mu m graphene oxide to prepare 6-30 mg/ml concentration graphene oxide aqueous solution, adding 0.1-5% mass fraction of auxiliary agent, where the auxiliary agent is inorganic salt, organic small molecule or macromolecule, ultrasonic dispersing, pouring into a mold plate, drying graphene oxide film and carrying out reduction with a reducing agent, (ii) heating the reduced graphene film under an inert gas atmosphere at 500-800 degrees C at rate of 0.1-1 degrees C/minute and insulating for 0.5-2 hours, (iii) heating under an inert gas atmosphere at 1000-1300 degrees C at rate of 1-3 degrees C/minute for 0.5-3 hours, (iv) heating to 2500-3000 degrees C under an inert gas atmosphere at rate of 5-8 degrees C/minute for 0.5-4 hours and natural cooling to obtain a porous graphene film, and (v) pressing the graphene film under high pressure.