Preparation of lithium iron phosphate nano composite microsphere

The invention discloses a method for preparing a lithium iron phosphate nano composite microsphere for a lithium-ion secondary battery anode material by a hydrothermal method, which comprises the following steps: evenly mixing a lithium source, an iron source and a phosphoric acid source according to the stoichiometric ratio of 1-1.05:1:1 to prepare an aqueous solution with certain concentration, adding proper amount of reducing agent, carbonizing agent, ion dopant and the like into the aqueous solution, growing and curing crystals under high-temperature hydrothermal condition, removing a solvent from a hydrothermal product, and burning the hydrothermal product in inert or reducing atmosphere to obtain a final product. The lithium iron phosphate anode material prepared by the method has a regular nano composite microsphere structure, has a particle diameter of between 2 and 4 mu m, even distribution, tap density up to 1.3 to 1.6 g/cm, and has excellent cycle performance and multiplying power performance. The method has simple and easily-controlled process, can use cheap trivalent iron as the iron source, can obtain rich raw materials, and is a practical technique for preparing lithium iron phosphate.