▎ 摘　　要

NOVELTY - A graphene composite film modified by single crystal sapphire whiskers comprises graphene and single crystal sapphire whiskers, where graphene forms substrate film layer; single crystal sapphire whiskers are dispersed in substrate film layer; and content by weight of graphene is greater than that of single crystal sapphire whiskers. USE - A graphene composite film modified by single crystal sapphire whiskers for electrode for use in lithium ion batteries and capacitors (claimed). ADVANTAGE - The graphene composite film has excellent toughness, structural stability, and folding resistance, as well as excellent electroconductivity and thermoconductivity; and the preparation method is good in reproducibility and low in cost. The electrode has stable structure, low internal resistance, and excellent electroconductivity, thermoconductivity, cycle performance, and rate performance during usage, as well as charging and discharging. The preparation method of the graphene composite film is effective for uniformly dispersing the single crystal sapphire whiskers and uniformly blending the same in the substrate film layer formed from the graphene, achieving a synergistic interaction effect between the two to endow the prepared graphene composite film with excellent toughness, electroconductivity, and thermal resistance simultaneously. Moreover, the preparation method has easily controllable conditions and good reproducibility, and the graphene composite film has stable performance, reducing cost. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) preparation of graphene composite film modified by single crystal sapphire whiskers which involves dispersing single crystal sapphire whiskers into graphene oxide solution to prepare dispersion, where concentration by weight of graphene oxide is greater than that of single crystal sapphire whiskers, forming film from dispersion to obtain graphene oxide composite film, and reducing graphene oxide composite film; and (2) electrode comprising the graphene composite film.