▎ 摘　　要

NOVELTY - The method involves preparing a graphene: a graphene oxide solid powder is dispersed in distilled water to form a sol solution. A graphene oxide solid is formed and addes a metal magnesium strip or a metal aluminum strip to the liquid, heating at 60-90 degrees C for 2-10 minutes, taking out the unreacted metal magnesium strip or metal aluminum strip, and the reaction solution is ultrasonicated for 1-5 minutes to obtain a graphene suspension. The 60%-80% nitric acid is added to the graphene oxide suspension, and superheating reaction at room temperature for 0.5h-2h, and filtering obtains deep graphene oxide. The preparing capacitor: The above graphene, polyvinylidene fluoride binder and conductive agent acetylene black are mixewd into a solvent to prepare a slurry, applying the slurry to a current collector to prepare an electrode sheet. The electrode sheet and the separator are assembled and immersed in an electrolyte to obtain a capacitor. USE - Method for preparing graphene-based capacitor with ultra-high energy density. ADVANTAGE - The preparing method is simple in operation. The edge of the finally prepared graphene contains large amount of carbonyl groups, which exerts tantalum capacitance, and the two graphene sheets provide a double-layer capacitance, thus improving the supercapacitor when the graphene is applied to the electrode material of the specific capacity.