▎ 摘　　要

NOVELTY - Preparing graphene comprises adding natural graphite and mixed acid in a reaction kettle, magnetic stirring, then slowly adding potassium permanganate to react, cooling and diluting, adding hydrogen peroxide into obtained solution, acid washing the graphite oxide solution, centrifugally washing to remove sulfate radical ion, adjusting the pH value, mixing viscous liquid and organic solvent, adding the mixture into an ultrasonic oscillator for oscillating, freezing and drying, heating preserving, cooling the mixture, grinding, dispersing the grinded powder in organic solvent, and drying. USE - The method is useful for preparing graphene (claimed), which is useful in lithium ion battery, super capacitor and solar energy battery. ADVANTAGE - The method is capable of simply preparing graphene with high-quality, little time consumption, good conductivity and cheap raw material in a cost-effective manner. DETAILED DESCRIPTION - Preparing graphene comprises adding 1 g of natural graphite and 40-100 ml of mixed acid in a reaction kettle, magnetic stirring to mix at temperature of lower than 20 degrees C, then slowly adding 3 g of potassium permanganate, sealing the reaction kettle to react at constant temperature of 60-90 degrees C and stirring at magnetic force for 4 hours, cooling to room temperature, then diluting into 400 ml of solution, adding 2-6 ml of hydrogen peroxide into the obtained solution to obtain light yellow iron oxide graphite solution, acid washing the graphite oxide solution by adding 4.5-5.5% of sulfuric acid solution for 2-4 times using differential centrifugation method, centrifugally washing graphite oxide solution for 5-6 times using deionized water, removing sulfate radical ion, adjusting the pH value to 6-7 to obtain graphite oxide viscous liquid, mixing graphite oxide viscous liquid and 1-3 volume of organic solvent, adding the mixture into an ultrasonic oscillator for oscillating under ultrasonic power of 100-600 W for 1-2 hours, freezing and drying to obtain graphene oxide, drying the graphene oxide in a tubular furnace under low air condition, then heating at 290-310 degrees C and speed of 8-12 degrees C/minutes for reduction treatment, heat preserving the temperature for 2-5 minutes, heating at 1000-1050 degrees C under the protection of lower nitrogen for 1-3 hours, cooling the mixture to room temperature, then grinding, ultrasonically dispersing the grinded powder in organic solvent, and drying at 50-60 degrees C to obtain graphene powder. The mixed acid is concentrated sulfuric acid and concentrated phosphoric acid with volume ratio of 7:3-9:1. The organic solvent is alcohol, ketone or aldehyde.