▎ 摘　　要

NOVELTY - Preparing manganese(II,III) oxide/reduced graphene oxide (Mn3O4/RGO) nano-composite material comprises e.g. (i) uniformly mixing phosphorus pentoxide and potassium persulfate, dissolving in certain amount of concentrated sulfuric acid, heating, adding natural graphite, incubating; (ii) cooling to room temperature, diluting; (iii) uniformly mixing the precursor with concentrated sulfuric acid in an ice bath; (iv) diluting; (v) suction filtering; and (vi) dissolving graphene oxide in deionized water, dispersing uniformly, adding manganese acetate tetrahydrate and adding potassium hydroxide. USE - The Mn3O4/RGO nano-composite material is useful as cathode of lithium ion battery (claimed) and capacitor. ADVANTAGE - The nano-composite material has good electrochemical performance. The method is simple. DETAILED DESCRIPTION - Preparing Mn3O4/RGO nano-composite material comprises (i) uniformly mixing phosphorus pentoxide and potassium persulfate in the mass ratio of 1:1, dissolving in certain amount of concentrated sulfuric acid, heating to 80 degrees C, adding 3-5 g natural graphite, incubating at constant temperature for 4 hours; (ii) cooling to room temperature, diluting with 300-400 ml deionized water, incubating overnight, washing, filtering and drying at 60 degrees C in a vaccum oven, to obtain a precursor; (iii) uniformly mixing the precursor with 120 ml concentrated sulfuric acid in an ice bath, adding 0.09-0.11 mol potassium permanganate under slow stirring conditions, incubating under constant temperature at 0-5 degrees C, stirring uniformly at 35 degrees C; (iv) diluting the step (iii) product by adding 250-300 ml water, placing in a ice bath at 30 degrees C, stirring uniformly and adding sufficient amount of deionized water, then adding 20 ml 30% hydrogen peroxide, carrying out reaction, until the mixture bubbles and the color turns bright yellow; (v) suction filtering the step (iv) product, washing with 1 l dilute hydrochloric acid in the mass ratio of 1:10, removing a portion of the metal ions by filtration, washing with deionized water, removing excess acid, dissolving in water, sonicating and dispesing uniformly, to obtain graphene oxide solution, centrifuging an drying to obtain brown-black graphene oxide product; and (vi) dissolving 100 mg graphene oxide in 100 ml deionized water, dispersing uniformly, adding 2.45 g manganese acetate tetrahydrate, then adding 1 mol/l potassium hydroxide under stirring conditions, adjusting pH to 10, stirring continuously for 5 minutes, transferring into a autoclave, carrying out reaction at 160 degrees C for 6, 24 and 72 hours, to obtain reaction product at different times, washing repeatedly with water and freeze-drying for 8 hours, to obtain the final product.