The invention discloses in-situ carbon-coated multi-cation doped
lithium manganese iron phosphate and a preparation method thereof, the preparation method comprises the following steps: firstly synthesizing ternary
metal cation doped MnxFe1-x-a-b-cAaBbCc-MOF through a solvothermal method, wherein x is more than 0 and less than 1, a is more than 0 and less than 0.04, b is more than 0 and less than 0.04, c is more than 0 and less than 0.04, and a + b + c is equal to 0.05; a, B and C are respectively one of doped
metal elements Mg, Ti, V, Co, Ni, Cr, Zn, Cu, Zr and Nb, and A, B and C are different from one another; and then mixing the in-situ carbon-coated multi-cation doped
lithium manganese iron phosphate serving as a precursor with a
lithium source and a
phosphorus source,
grinding, spray-
drying, and calcining in an
inert atmosphere to obtain the in-situ carbon-coated multi-cation doped lithium
manganese iron phosphate. According to the invention, atomic-scale uniform distribution of iron and manganese
metal elements and three doped cations in the lithium manganese iron
phosphate can be realized, the synergistic effect of the doped metal cations is fully exerted, the
structural stability of the material is improved, and the electrochemical performance of the lithium manganese iron
phosphate is further optimized.