▎ 摘　　要

NOVELTY - Preparing high-performance iron phosphate/graphene complex cathode material comprises (i) measuring mass concentration of whole iron in iron vitriol slag hydrochloric acid leaching liquid and mass concentration of hydrogen ion, (ii) taking iron vitriol slag hydrochloric acid leaching liquid obtained in step (i) into beaker, adding distilled water into beaker with stirring, adding graphene oxide dispersion liquid to beaker according to mass ratio of graphene oxide to theoretically generated iron phosphate of 10-40%, ultrasonically processing, adding hydrogen peroxide and sodium phosphate tribasic dodecahydrate to beaker, and making molar ratio of phosphate ion and iron ion in solution to be 1:1.5, (iii) carrying out reaction of solution with magnetic stirring, allowing to stand, and finally filtering, washing and freezing and drying precipitate to constant weight to obtain precursor, and (iv) transferring precursor obtained in step (iii) into tubular furnace, and heating. USE - The method is useful for preparing high-performance iron phosphate/graphene complex cathode material liquid, which is useful for preparing high-performance lithium ion batteries (claimed). ADVANTAGE - The method: is simple, economical, easy to control the preparation conditions, and suitable for large-scale production; has high in yield; and makes complete use of iron resources in the iron vitriol slag. The material: has good lithium storage performance as a cathode material for lithium ion batteries. DETAILED DESCRIPTION - Preparing high-performance iron phosphate/graphene complex cathode material comprises (i) measuring mass concentration of whole iron in iron vitriol slag hydrochloric acid leaching liquid and mass concentration of hydrogen ion, where the mass concentration of iron is 0.255 mol/l, and mass concentration of the hydrogen 1.23 mol/l, (ii) taking 20 ml iron vitriol slag hydrochloric acid leaching liquid obtained in step (i) into beaker, adding 20 ml of distilled water into a beaker with stirring at room temperature, adding graphene oxide dispersion liquid with mass concentration of 1 mg/ml to beaker according to mass ratio of graphene oxide to theoretically generated iron phosphate of 10-40%, ultrasonically processing for 1 hour, adding 2 ml hydrogen peroxide and 2.9 g sodium phosphate tribasic dodecahydrate to beaker, and making molar ratio of phosphate ion and iron ion in solution to be 1:1.5, (iii) carrying out reaction of solution obtained in step (ii) at constant temperature of 70degreesC with magnetic stirring for 0.5 hour, allowing to stand at room temperature for 3 hours, and finally filtering, washing and freezing and drying precipitate to constant weight to obtain precursor, and (iv) transferring precursor obtained in step (iii) into tubular furnace, heating from room temperature to 400degreesC in argon atmosphere at heating rate of 2degreesC/minute, and keeping at 400degreesC for 6 hours, where the mass concentration of total iron is sum of mass concentrations of iron ions (Fe3+) and ferrous ions (Fe2+).