Multi-metal composite oxide coated modified lithium manganate positive electrode material and preparation method thereof

A multi-metal composite oxide coated modified lithium manganate positive electrode material takes lithium manganate as a matrix, wherein the surface of the matrix is coated with a Li(M1)beta(M2)gammaO2 coating layer, beta is larger than 0 and smaller than or equal to 1, gamma is larger than 0 and smaller than or equal to 0.5, and M1 is at least one of Mn, Co and Ni; and M2 is at least one of Al, Mg, Zr, Ti, Sr, Y, W, Bi, La, Sd, Ba, Ce, V, Se, Mo, Nb and B. The preparation method comprises the following steps of: mixing the raw materials according to a stoichiometric ratio for preparing a lithium manganate matrix, and calcining the mixture at the temperature not lower than 900 DEG C to obtain a first calcined product; and mixing the calcined product with a M1-containing compound and a M2-containing compound, and calcining to obtain the multi-metal composite oxide coated modified lithium manganate positive electrode material. The modified lithium manganate positive electrode material disclosed by the invention