Graphene composite material and preparation method thereof

The invention provides a graphene composite material and a preparation method thereof. The preparation method comprises the steps that graphite powder, potassium sulphate, phosphorus pentoxide and concentrated sulfuric acid are mixed, heated, reacted, filtered, washed to be neutral and dried, the mixture is mixed with concentrated sulfuric acid, potassium permanganate is slowly added and stirred, deionized water and hydrogen peroxide are added, filtration is carried out, the mixture is washed to be neutral and dried, and the mixture is mixed with deionized water for ultrasonic treatment; silver nitrate and deionized water are mixed, and ammonium hydroxide is dropwise added; the product is mixed and stirred, carbon nano tube, stannic oxide, tea polyphenol, potassium sorbate, glucose and deionized water are added, the mixture is heated, stirred, filtered, washed to be neutral and dried, the product is mixed with hydrogenated carboxyl nitrile rubber, N,N-dimethyl formamide and dicumyl peroxide with stirring, and finally the product is added into a press vulcanizer to be vulvanized and molded. The graphene composite material has good tensile property, and is remarkable in elasticity and tenacity, high in heat conductivity and wide in application range.