▎ 摘　　要

NOVELTY - Production of graphene oxide involves oxidizing graphite in a mixture of phosphoric and sulfuric acids, stirring the graphite and acid mixture, adding potassium permanganate to the mixture, stirring the mixture in ice bath to form a graphene oxide-dispersion, adding preset volume of water, and stirring water and dispersion, heating, cooling the dispersion to room temperature, adjusting the pH of the dispersion to 7.0-7.6, adding excess alcohol, isolating the graphene oxide by centrifugation, and washing with acid, water and then alcohol, and collecting the solid graphene oxide. USE - Production of graphene oxide used in energy storage device, battery and supercapacitor. ADVANTAGE - The method efficiently and economically produces graphene oxide having improved performance and reduced amount of impurities within a short period of time. DETAILED DESCRIPTION - Production of graphene oxide involves oxidizing graphite in a mixture of phosphoric and sulfuric acids, stirring the graphite and acid mixture in an ice bath for 10 minutes-2 hours, adding potassium permanganate to the graphite-acid mixture in a ratio 1 :3-1 :9, stirring the mixture in an ice bath for 10 minutes-2 hours to form a graphene oxide-dispersion, adding water having a pH 0-3 and a volume about one-fourth of the starting acid volume to the dispersion, and stirring the water and dispersion for 10 minutes-2 hours, heating the dispersion to 60-120 degrees C for 6 minutes to 8 hours, cooling to room temperature, adjusting the pH of the dispersion to 7.0-7.6, adding excess alcohol to the graphene oxide-dispersion, isolating the graphene oxide by centrifugation, and washing the isolated graphene oxide with acid, water and alcohol until the effluent reaches a pH of 7.0-7.2, and collecting the graphene oxide solids. The ratio of phosphoric to sulfuric acid in the acid mixture is from 1:3-1:9 by volume. The pH adjusting step comprises adding sodium carbonate, sodium hydroxide, potassium hydroxide, potassium carbonate or calcium carbonate. The alcohol is selected from methanol, ethanol, propanol, isopropanol, and butanol. INDEPENDENT CLAIMS are included for the following: (1) population of reduced graphene oxide particles, having a specific capacitance of greater than 250 F g-1 at a current of l A g-1; and (2) energy storage device comprising graphene oxide, which involves diluting the isolated graphene oxide in water, dispersing the diluted graphene oxide with sonication, heating the dispersed graphene oxide for about 24 hours at 180 degrees C and isolating the reduced graphene oxide.