▎ 摘　　要

NOVELTY - A graphene-doped nano-rich lithium manganese iron phosphate synthesizing method at atmospheric aqueous phase, involves preparing lithium phosphate, graphene or graphene oxide aqueous suspension, and bivalent manganese salt and ferrous salt solution, and mixing lithium phosphate, graphene or graphene oxide aqueous suspension, and bivalent manganese salt and ferrous salt mix solution. The obtained mixture is solid-liquid separated, washed and dried to obtain graphene-doped nano-rich lithium manganese iron phosphate-containing liquid. USE - Method for synthesizing graphene-doped nano-rich lithium manganese iron phosphate at atmospheric aqueous phase. ADVANTAGE - The method enables synthesizing graphene-doped nano-rich lithium manganese iron phosphate under mild conditions, with low cost, high capacity electrical properties, good rate capability, batch stability and controlled particle size uniformity, reduces production cost, recovers lithium liquid and meets industrial production requirements. DETAILED DESCRIPTION - A graphene-doped nano-rich lithium manganese iron phosphate synthesizing method at atmospheric aqueous phase, involves preparing lithium phosphate, graphene or graphene oxide aqueous suspension, and bivalent manganese salt and ferrous salt solution. Preparation of lithium phosphate is performed by adding phosphoric acid to lithium-containing salt solution containing 0.2-3 mol/l lithium, increasing temperature of the mixture to 30-70 degrees C, adding sodium hydroxide solution to mixture, stirring the mixture, regulating pH value of the mixture to 9.5-11, separating the mixture to solid and liquid and washing solid to obtain lithium phosphate. Preparation of graphene or graphene oxide aqueous suspension is carried out by adding pure water to graphene or graphene oxide, and performing ultrasonic dispersion. Lithium phosphate and graphene or graphene oxide aqueous suspension are mixed to obtain suspension with concentration of 0.1-0.5 mol/l. Bivalent manganese salt and ferrous salt mix solution is prepared by by dissolving bivalent manganese salt and ferrous salt in water to obtain solution with manganese iron total content of 0.5-3 mol/l and pH value of 1-3. Lithium phosphate and graphene or graphene oxide aqueous suspension is added to a reaction kettle, stirred under normal pressure, and heated. Bivalent manganese salt and ferrous salt mix solution is added to hot solution and maintained at 1-3 degrees C for 2-8 hours. The obtained mixture is solid-liquid separated, washed and dried to obtain graphene-doped nano-rich lithium manganese iron phosphate-containing liquid. Obtained liquid is added to a reaction kettle and stirred. Lithium phosphate is added to the liquid and temperature is increased to 30-70 degrees C. Sodium hydroxide solution is added to mixture and pH value is regulated to 9.5-11. Obtained mixture is solid-liquid separated and washed to recover lithium phosphate.