▎ 摘　　要

NOVELTY - The method for preparing high electrical performance graphene nanosheet, involves adding flake graphite and sodium nitrate to concentrated sulfuric acid, gradually adding potassium permanganate, adding hydrogen peroxide to obtain oxidized flake graphite, heating, introducing inert gas, adding ethanol, milling, adding graphene quantum dots, ball milling, preparing suspension, centrifuging for 20 minutes to obtain graphene nanosheet suspension, recycling the graphene quantum dots through pressure filtering process. USE - Method for preparing high electrical performance graphene nanosheet (claimed) for use in lithium battery. ADVANTAGE - The environmentally-friendly method enables simple and economical preparation of reusable high electrical performance graphene nanosheet with high electrochemical performance, improved dispersibility, high stability and excellent energy saving effect, and effectively prevents the reduction of lithium storage capacity caused by the reduction in the size of the ball milling process. DETAILED DESCRIPTION - Method for preparing high electrical performance graphene nanosheet, involves (S1) adding flake graphite and sodium nitrate to concentrated sulfuric acid, gradually adding potassium permanganate while maintaining temperature at 20 degrees C, stirring at low temperature for 1-2 hours, heating at 35-40 degrees C, stirring for 30 minutes, heating at 65-80 degrees C, adding hydrogen peroxide for 40 minutes, centrifuging, filtering, washing, vacuum drying to obtain oxidized flake graphite, (S2) placing the oxidized flake graphite in heating furnace, heating at 260-305 degrees C at the rate of 9.0 degrees C/minute, introducing inert gas at the rate of 3000 ml/minute, (S3) carrying out liquid-phase stripping and wet grinding, adding ethanol, milling, adding graphene quantum dots as additives in ball ratio of 400-600:1, adding 4-8 wt.% graphene quantum dots, ball milling with a planetary ball mill at 400-600 rpm for 4-6 hours, preparing suspension, centrifuging for 20 minutes to obtain graphene nanosheet suspension, (S3) recycling the graphene quantum dots through pressure filtering process.