▎ 摘　　要

NOVELTY - Preparation of ternary material coated with polyaluminum-graphene involves: mixing polyvinylpyrrolidone with liquid medium while stirring, adding a graphene powder and performing ultrasonic vibration treatment to obtain a graphene solution; mixing the graphene solution and a diluted solution to obtain a polyaluminum-graphene solution; uniformly mixing a ternary material and the liquid medium into a mixed solution (2); uniformly mixing the polyaluminum-graphene solution and the mixed solution (2) into a mixed solution (3); dripping aqueous ammonia until the acidity of the solution falls within pH of 8-12 and aging the mixture at any temperature in the temperature ranged of 50-95 degrees C for 5-48 hours to obtain a precursor (1); vacuum-drying the precursor (1) at any temperature in the range of 150-260 degrees C to obtain a dried precursor (2); and placing the dried precursor (2) in a pure oxygen atmosphere. USE - The method is useful for preparing a ternary material coated with polyaluminum-graphene. DETAILED DESCRIPTION - Preparation of a ternary material coated with polyaluminum-graphene involves: mixing polyvinylpyrrolidone having a molecular weight of 2000-70000 with 10 times the volume of a liquid medium while stirring, adding a graphene powder with volume of 1-10 times the volumes of the polyvinylpyrrolidone and performing ultrasonic vibration treatment for 10 minutes to 3 hours to obtain a graphene solution; mixing the graphene solution and a diluted solution in a volume ratio of 1:1 to obtain a polyaluminum-graphene solution; uniformly mixing the ternary material with a particle size (D50) of 1 nm to 50 mu m and the liquid medium in a volume ratio of 1:(0.1-1000) into a mixed solution (2); uniformly mixing the polyaluminum-graphene solution and the mixed solution (2) in a volume ratio of 1:1 into a mixed solution (3); dripping aqueous ammonia until the acidity of the solution falls within the pH range of 8-12 under continuous stirring conditions and aging the mixture at any temperature in the temperature range of 50-95 degrees C for 5-48 hours to obtain a precursor (1); vacuum-drying the precursor (1) at any temperature in the temperature range of 150-260 degrees C to obtain a dried precursor (2) or spray drying at any temperature in the temperature range of 150-260 degrees C to prepare a dried precursor (2); and placing the dried precursor (2) in a pure oxygen atmosphere, and using a programmed heating method or a step-by-step heating method to prepare a ternary positive electrode material having a layered alpha -sodium iron dioxide structure and coated with polyaluminum-graphene. The diluted solution is a solution obtained by removing sulfate ions in a polyaluminum sulfate solution by using a barium carbonate method, a membrane separation method, an ion exchange method, or a zirconium hydroxide method, or removing chloride ions in the polyaluminum chloride solution by a silver carbonate method, a membrane separation method, an ion exchange method or a zirconium hydroxide method. The polyaluminum sulfate solution is a solution in which polyaluminum sulfate is dissolved in water and diluted with water to form a Al13((AlO4Al12(OH)24(H2O)12)7+) solution with concentration of 0.00001-20000 mmol/l, or the aluminum chloride is dissolved in water and diluted with water to obtain a solution with a concentration in the range of 0.00001-20000 mmol/l. The ternary material simultaneously meets the following characteristics, preferably the diffraction peaks on the X-ray powder diffraction (XRD) pattern are all consistent with the characteristic diffraction peaks of the layered alpha -sodium iron dioxide structure of joint committee on powder diffraction standards (JCPDS) card 09-0063. According to the prepared buckle type half-cell under the current of 0.2C rate and the first charge-discharge cycle, the ratio of charging to a constant current of the lithium electrode to 4.6V and charging to 4.4V to increase the specific charge capacity is less than 25%. No diffraction peak corresponds to lithium manganite of JCPDS card 27-1252 in the 2 theta angle of 20-25 degrees of the sample XRD diffraction pattern. The particle size (D50) is the particle size corresponding to the cumulative particle size distribution percentage of the sample reaching 50%.