The invention discloses a
graphene film with ultrahigh flexibility and high
thermal conductivity and a preparation method of the
graphene film. The
graphene film is prepared from an ultralarge uniform graphene
oxide sheet through steps of solution film-formation,
chemical reduction, high-temperature reduction, high-pressure compression and the like. The graphene film is formed through physical crosslinking of macroscopic multi-layer folded graphene with microscale folds, and inter-lamella slippage can be realized, so that the graphene film has ultrahigh flexibility. The graphene
lamellar structure of the graphene film is perfect, the lamellas have ultralarge crystalline areas which are about 100 mu m and contain few defects, the structure is compact after high-pressure compression, and the graphene film has ultrahigh electrical
conductivity and
thermal conductivity. The graphene film with ultrahigh flexibility and high
thermal conductivity can be bent repeatedly more than 1,200 times, the elongation at break is 12%-18%, the electrical
conductivity is 8,000-10,600 S / cm, the thermal
conductivity is 1,800-2,600 W / mK, and the graphene film can be used as a high-flexibility, thermal-conducting and electric-conducting device.