Anion-cation double-doped lithium iron phosphate anode material and preparation method thereof

The invention discloses an anion-cation double-doped lithium iron phosphate anode material and a preparation method thereof, and belongs to the field of new energy materials. The anode material is a compound of magnesium-fluorine double-doped lithium iron phosphate and carbon, the magnesium ion part replaces the position of a iron ion in a lithium iron phosphate crystal, and the fluoride ion part replaces the position of a phosphoric acid ion in the lithium iron phosphate; main components of the anode material can be expressed as follows: LiFe(1-x)Mgx(PO4)(1-y)F3y/C, wherein x is equal to or greater than 0.001 and is equal to or less than 0.1, and y is equal to or greater than 0.001 and is equal to or less than 0.1. The anode material is prepared by using raw materials of lithium sources, ferrous sources, phosphorus sources, magnesium sources, fluorine sources and carbon sources through a high temperature solid phase method. According to the invention, positive active materials adopts the characteristics of high rate capability, good cycling performance, and the like of a positive active material, so that the capacity remains 98 mAh/g under 10C multiplying power, and the capacity retention ratio remains 98.4% under 1C multiplying power for the circulation of 150 times.