▎ 摘　　要

NOVELTY - Preparing graphene/manganese dioxide composite material comprises ultrasonically processing organic solvent including e.g. tetrahydrofuran or ethanol into graphite to obtain dispersion liquid, where graphite is graphite powder or natural crystalline graphite flake, rotating, taking the supernatant to obtain graphene dispersion liquid, ultrasonically processing with manganese ion salt solution, taking positively charged graphene dispersion liquid as an electrolyte, taking conductive substrate made of copper, aluminum, nickel or stainless steel, depositing on the cathode sheet, and drying. USE - The method is useful for preparing graphene/manganese dioxide composite material (claimed). ADVANTAGE - The method: prepares graphene liquid by ultrasonic stripping process without oxidation treatment and with less defects; maintains the complete structure of graphene; utilizes electrodeposition method, which ensures uniform three-dimensional conductive surface of the substrate and controllable deposition of graphite/manganese dioxide composite material; and is simple, economical and easy to control. DETAILED DESCRIPTION - Preparing graphene/manganese dioxide composite material, comprises (a) adding 1 l organic solvent 1 into 1 g graphite, ultrasonically processing at 20-40 degrees C at a power of 200 W for 2-20 hours to obtain dispersion liquid, where the organic solvent is 1-methyl-2-pyrrolidone, tetrahydrofuran, dimethylformamide, butyrolactone, acetone or ethanol, and the graphite is graphite powder or natural crystalline graphite flakes, rotating the dispersion at a speed of 4000 revolutions/minute for 0.5-2 hours, taking the supernatant to obtain graphene dispersion liquid, (b) adding 1 l organic solvent 2 into 1 g manganese ion salt to obtain manganese ion salt solution, where the organic solvent 2 is same as the organic solvent 1, mixing the manganese ion salt solution with graphene dispersion liquid, where the concentration of manganese ion is 0.1-10 mmol/l and solid content of the graphite is 0.01-0.1 g/l, ultrasonically processing for 30 minutes for the adsorption of manganese ion with positive charge on the graphene to obtain positively charged graphene dispersion liquid, where manganese salt is manganese nitrate, manganese chloride, manganese sulfate or manganese acetate, and (c) taking the positively charged graphene dispersion liquid as an electrophoretic deposition electrolyte in an electrophoretic deposition tank to deposit on a conductive substrate made of copper, aluminum, nickel or stainless steel, coated with copper, aluminum, nickel or stainless steel, or a conductive material as conductive substrate, taking as a cathode sheet without restricting the composition of the material and 3-dimensional structure of the conductive substrate, depositing the graphene dispersion liquid on the cathode sheet, placing in an oven and drying at 80 degrees C for 12 hours to obtain cathode sheet with single-layer graphene surface/manganese dioxide composite material, where the distance between the anode and cathode sheets during the deposition process is 50 mm, the voltage applied is 10-100 V, and the electric pulse deposition process is carried out at 40-120 degrees C for 1-60 minutes.