▎ 摘　　要

NOVELTY - Preparation of lithium-philic graphene quantum dot/lithium composite material involves dissolving 0.1-0.3 g citric acid and 0.2-0.7 g thiourea in 5-15 ml deionized water, pouring obtained reaction liquid into hydrothermal kettle, sealing in oven, hydrothermally reacting for 4-6 hours at 140-180 degrees C, cooling reaction liquid to room temperature, using 0.5-1 mol/L sodium hydroxide to adjust pH to 5-6, using dialysis bag of 3000-4000 Da molecular weight cut-off dialysis for 4-8 hours, freeze-drying for 24-48 hours to obtain target product lithium-philic graphene quantum dot material, dissolving lithium-philic graphene quantum dot material in mixed solution of dimethyl sulfoxide and acetonitrile at volume ratio of 3:4-6, spin-coating lithium-philic graphene quantum dot solution on lithium metal surface at speed of 1000-2000 rpm for 60-90 seconds, and repeating spin-coating for 1-5 times to obtain lithium-philic graphene quantum dot/lithium composite material having thickness of 20-100 nm. USE - Preparation of lithium-philic graphene quantum dot/lithium composite material used as cathode material for lithium-air battery (all claimed). ADVANTAGE - The preparation method is simple, can realize lithium metal negative electrode with long cycle life under large current and large capacity, and has good application prospect in the field of fast charging of high-energy density batteries. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for application of the lithium-philic graphene quantum dot/lithium composite material as cathode material of lithium ion battery, which involves: (A) using lithium bis(trifluoromethanesulfonyl)imide as electrolyte salt, 1,3-dioxolane and 1,2-ethylene glycol dimethyl ether as electrolyte solvent, and lithium nitrate as electrolyte additive to form battery electrolyte; and (B) using Celgard 2400 (RTM: polypropylene membrane) as separator and lithium-philic graphene quantum dots/lithium composite material as negative electrode to assemble a symmetrical battery, where the volume ratio of 1,3-dioxolane and 1,2-ethylene glycol dimethyl ether is 1:(1-2), the concentration of lithium bis(trifluoromethanesulfonyl)imide is 0.5-1.5 mol/L, and the concentration of lithium nitrate is 2-5 wt.%.