▎ 摘　　要

NOVELTY - Preparing graphene quantum dot with uniform size involves preparing graphene oxide by using graphite powder, sodium nitrate, potassium permanganate, and concentrated sulfuric acid as raw materials, and using hummers method graphene oxide powder, dispersing 25-100 milligram graphene oxide in 50 milliliter concentrated nitric acid solution, and ultrasonically treating for 2-6 hours to obtain a yellowish orange dispersion. USE - Method for preparing graphene quantum dot with uniform size used as electrode material of an energy storage device (claimed). ADVANTAGE - The method enables to prepare graphene quantum dot with uniform size in simple manner under mild conditions, which exhibits excellent conductivity, has high specific capacity, excellent rate performance, fast ion absorption and transmission rate and circulation service life, and has good application potential in energy storage device field. DETAILED DESCRIPTION - Preparing graphene quantum dot with uniform size involves preparing graphene oxide by using graphite powder, sodium nitrate, potassium permanganate, and concentrated sulfuric acid as raw materials, and using hummers method graphene oxide powder, dispersing 25-100 milligram graphene oxide in 50 milliliter concentrated nitric acid solution, and ultrasonically treating for 2-6 hours to obtain a yellowish orange dispersion. The dispersion is transferred to a teflon-lined stainless steel autoclave closed and reacted at 80-180 degrees C for 8-24 hours, cooled to room temperature, solution is centrifuged at 8000 revolutions per minute \for 10 minutes to remove the supernatant liquid, and resulting pale yellow slurry is laced in a petridish and dried naturally in a well-ventilated place. The sample is placed in a tube furnace and calcined under high temperature in an argon atmosphere to collected bright black products to obtain final product.