▎ 摘　　要

NOVELTY - Graphene filler comprises the stacked graphene sheet; graphene filler is sheet-shaped, orientation factor σ orientationof the graphene sheet is 70-95%; where, σ orientation = α orientationX P No-pore; α orientation is Hermans ordered parameter of graphene sheet; testing and calculating P No-pore by: using focused ion beam (FIB) to cut along the lamellar direction perpendicular to described graphene filler under assistance of scanning electron microscope, obtaining section, on section, using image J software to analyze a random square area of 2 μm2, the pore area ratio P pore on cross section = internal pore area S pore /2 μm2, P No-pore= 1-P pore. USE - The graphene filler is useful for composite heat-conducting material used in electronic device. ADVANTAGE - The graphene filler: has a thicker sheet diameter, can resist wrinkles and bending during the dispersion process of the matrix, and can improve orientation, thus improving thermal conductivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: Preparing the graphene filler comprising mixing the graphene oxide slurry comprising polar solvent with polymer soluble in polar solvent to obtain the slurry to be coated, coating the slurry to be coated on the base film to form a graphene oxide film, drying, peeling the graphene oxide film from the base film to obtain a graphene oxide film; sequentially subjecting graphene oxide film to heat treatment, carbonization treatment and graphitization treatment to obtain a thermally reduced graphene oxide film; molding the thermally reduced graphene oxide film; crushing obtained thermally reduced graphene oxide film after molding, obtaining the graphene filler. Composite heat-conducting material comprising the graphene filler.