Modified lithium manganese phosphate composite anode material and preparation method thereof

The invention discloses a modified lithium manganese phosphate composite anode material and a preparation method thereof. The problem that an existing lithium manganese phosphate anode material is poor in conductivity, poor in rate capability and unstable in circulation is solved. The nominal molecular formula of the composite anode material disclosed by the invention is yLiMnPO4.(1-y)Na3V2(PO4)3-xF3x/C, wherein x is greater than or equal to 0 and smaller than or equal to 2; and y is greater than or equal to 0.75 and smaller than 1. The preparation method comprises the following steps: (1) carrying out mechanical activation dispersion of LiMnPO4 powder and modified precursor raw materials; (2) controlling to prepare a lithium manganese phosphate/vanadium-containing colloid precursor; and (3) carrying out a one-step calcination method to prepare a lithium manganese phosphate/sodium (fluoro)phosphate vanadium/carbon composite material. The modified lithium manganese phosphate composite anode material has the beneficial effects that the material is simple in technological process, uniform in dispersion and easy to control, and the synergistically modified LiMnPO4-based composite material is high in specific energy density, good in cycle performance and excellent in rate capability.