▎ 摘　　要

NOVELTY - Concentrated sulfuric acid, graphite powder and sodium nitrate are added to reactor, potassium permanganate and water are added, heated, hydrogen peroxide solution is added, stirred, filtered, washed, and dried, to obtain graphite oxide solid product. The obtained solid product is dispersed in water, centrifuged, and washed, to obtain graphene oxide suspension. Potassium permanganate is dissolved in the graphene oxide suspension, polyethylene glycol is added, filtered, washed with water and anhydrous ethanol, and dried, to obtain manganese oxohydroxide-graphene composite. USE - Preparation of graphene-based composite used for energy storage material for supercapacitor. ADVANTAGE - The method enables simple, efficient, easy, economical and quick preparation of graphene-based composite having high surface area and excellent electrochemical stability without addition of surfactant, templating agent and stabilizer. DETAILED DESCRIPTION - Concentrated sulfuric acid with concentration of 98%, graphite powder and sodium nitrate are sequentially added to a reactor, the reactor is placed in an ice water bath, potassium permanganate is added, temperature of the reactor is controlled to 6 degrees C, reacted for 30 minutes, heated to 35 degrees C, and stirred for 2 hours. Water is added to the resultant reaction mixture, heated to 90 degrees C, stirred for 30 minutes, water is added in a volume ratio of 23:450 with concentrated sulfuric acid, 30% hydrogen peroxide solution is added, stirred, filtered, washed with 5% hydrochloric acid and water until sulfate is completely removed, the resultant solid is placed in an oven, and dried, to obtain graphite oxide solid product. The obtained solid product is dispersed in water to form suspension with concentration of 0.1-2 mg/mL, ultrasonically treated for 90 minutes, centrifuged, washed, and lower sediment is removed, to obtain graphene oxide suspension. Potassium permanganate is dissolved in the graphene oxide suspension, polyethylene glycol is added, the resultant product is added to a polytetrafluoroethylene-lined reactor, then placed in a sealed stainless steel reactor, reacted at 150-180 degrees C for 10-12 hours, cooled to room temperature, filtered, washed with water and anhydrous ethanol, and dried, to obtain manganese oxohydroxide-graphene composite. The volume-mass ratio of concentrated sulfuric acid, graphite powder and sodium nitrate is 23:1:1.2. The mass ratio of potassium permanganate graphite powder is 3:1. The volume ratio of water and concentrated sulfuric acid is 23:200. The volume ratio of 30% hydrogen peroxide solution and concentrated sulfuric acid is 23:6. The mass-volume ratio of potassium permanganate and polyethylene glycol is 20:1. The volume ratio of graphene oxide suspension and polyethylene glycol is 5:1-10:1.