▎ 摘　　要

NOVELTY - Preparation of layered lithium-rich manganese-based/graphene nanobelt cathode composite material comprises reacting aqueous solution of nickel, cobalt and manganese, precipitating agent solution and complexing agent solution, aging, and processing obtained precipitate to obtain precursor powder; uniformly mixing precursor powder with lithium source, precalcining, grinding, and calcining to obtain lithium-rich manganese-based cathode material; adding cathode material to graphene nanobelt dispersion, stirring, vacuum freeze-drying, and sintering. USE - Method for preparing layered lithium-rich manganese-based/graphene nanobelt cathode composite material (claimed) for lithium ion battery. ADVANTAGE - The graphene nanobelt protects lithium-rich manganese-based cathode material from erosion in hydrofluoric acid, thus, improving high-voltage safety and thermal stability. The cathode material and graphene nanobelt are wound into a three-dimensional porous network structure which improves surface conductivity of cathode material and reduces electrochemical polarization in charging and discharging process, thus, improving multiplying power performance and cycle performance. DETAILED DESCRIPTION - Preparation of layered lithium-rich manganese-based/graphene nanobelt cathode composite material comprises: (A) dissolving certain stoichiometric ratio of nickel source, cobalt source and manganese source in deionized (DI) water to obtain 0.1-3 mol/L first solution, dissolving precipitating agent in DI water to obtain 0.1-6 mol/L second solution, and dissolving complexing agent in DI water to obtain 0.01-3 mol/L third solution; simultaneously feeding first, second and third solutions to reaction container at 0.001-200 mL/minute, reacting at 40-70 degrees C and pH 7-11.5 for 1-36 hours under continuous stirring at 500-1200 revolutions/minute (rpm), aging for 0-36 hours, collecting precipitate, washing, repeatedly centrifuging, and drying at 60-120 degrees C for 6-20 hours to obtain precursor powder; and uniformly mixing precursor powder with lithium source at certain stoichiometric ratio to obtain fourth solution, precalcining the fourth solution in air atmosphere at 400-700 degrees C for 1-12 hours, taking out precalcined product, grinding, and calcining in air atmosphere at 750-1000 degrees C for 6-24 hours to obtain xLi2MnO3.(1-x)LiNi0.65-yCoyMn0.35O2 cathode material, in which the mass of lithium source is 1-1.1% of theoretical value; and (B) adding graphene nanobelt having width of 5-50 nm and length-diameter ratio of 50-300 to dispersant at graphene nanobelt-dispersant stoichiometric ratio of 1:0.1-10, and ultrasonically dispersing in ice bath at 50-500 W for 0.5-5 hours to obtain dispersion; and adding prepared cathode material to the dispersion at cathode material-graphene nanobelt stoichiometric ratio of 200-10:1, ultrasonically mechanically stirring at 50-500 W and 60-600 rpm for 0.1-12 hours, vacuum freeze-drying for 6-24 hours to obtain xLi2MnO3.(1-x)LiNi0.65-yCoyMn0.35O2:GNRs composite material, and sintering in inert atmosphere at 300 degrees C for 0.5-2 hours to remove residual dispersant or other impurities. x=more than 0 to less than 1; and y=0-0.3.