▎ 摘　　要

NOVELTY - Fibrous single crystal sapphire-modified graphene composite film comprises graphene and fibrous single crystal sapphire, where the graphene constitutes a substrate film layer, the fibrous single crystal sapphire is dispersed in the substrate film layer, and the weight content of the graphene is greater than the content of the fibrous single crystal sapphire. USE - The graphene composite film is used in an electrode which is used in a lithium ion battery or a capacitor (all claimed). ADVANTAGE - The graphene composite film realizes a synergistic effect between the fibrous single crystal sapphire and the graphene substrate film layer, and has excellent toughness, mechanical strength, structural stability, flex resistance, electrical conductivity and thermal conductivity. The method is easy to control, stable, and cost-effective. The graphene composite film provides electrode with stable charge/discharge characteristics, low internal resistance, excellent electric conductivity, thermal conductivity, cycle characteristics and rate characteristics, expanded application range, and improved electrochemical characteristics. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing the graphene composite film, comprising dispersing the fibrous single crystal sapphire in a graphene oxide solution to prepare a dispersion liquid, forming a graphene oxide composite film by forming a film of the dispersion liquid, and reducing the graphene oxide composite film, where the mass concentration of graphene oxide is higher than the concentration of fibrous single crystal sapphire; and (2) an electrode comprising the graphene composite film.