▎ 摘　　要

NOVELTY - A phosphorus source, lithium source, iron source and resorcinol are added to aqueous solution of graphene and completely stirred. An alcoholic solution containing aqueous formaldehyde solution is added to mixed solution, stirred, crystallized, cooled, suction filtered, washed and dried, to obtain lithium-iron hydroxyphosphate-carbon-resorcinol-formaldehyde resin/reduced graphene oxide powder precursor. The powder precursor is subjected to high-temperature calcination, to obtain lithium iron phosphate-carbon/reduced graphene oxide multistage composite microspheres. USE - Preparation of lithium iron phosphate-carbon/reduced graphene oxide multistage composite microspheres used for electrochemical energy storage material and lithium-ion battery. ADVANTAGE - The method enables preparation of lithium iron phosphate-carbon/reduced graphene oxide multistage composite microspheres have tap density of 1.3 g/cm3 and excellent electrochemical lithium storage characteristics. The large area of reduced graphene oxide-reduced nanosheets enhances microconductivity and electron conductivity between microspheres. DETAILED DESCRIPTION - A phosphorus source, lithium source, iron source and resorcinol are added to aqueous solution of graphene and completely stirred. An alcoholic solution containing aqueous formaldehyde solution is added to mixed solution and completely stirred. The mixed solution is transferred to reactor, closed and constant-temperature crystallized under self-pressure. After completion of reaction, the mixture is cooled to room temperature. The precipitated product formed by solvothermal process is subjected to suction filtration, washed with deionized water and dried, to obtain lithium-iron hydroxyphosphate-carbon-resorcinol-formaldehyde resin/reduced graphene oxide powder precursor. The lithium-iron hydroxyphosphate-carbon-resorcinol-formaldehyde resin/reduced graphene oxide powder precursor is subjected to high-temperature calcination under protective atmosphere, to obtain lithium iron phosphate-carbon/reduced graphene oxide multistage composite microspheres. The molar ratio of phosphorus source, lithium source, iron source and resorcinol component is 1:1-6:0.25-3:0.05-5. The molar ratio of resorcinol and formaldehyde is 0.05-3:1. The addition amount of graphene oxide is 0.01-20 wt.% of theoretical yield of lithium-iron hydroxyphosphate. The formaldehyde aqueous solution has formaldehyde content of 35-40 %mass.