The invention provides a monocrystal ternary positive
electrode material, which has a
chemical formula of LiaNixCoyMnzMbO2, wherein a is greater than or equal to 1.02 and less than or equal to 1.25, x + y + z + b is equal to 1, the average valence state of Ni, Co and Mn is 3.0+ / -0.1, the
molar ratio of Co is 0-20%, the
molar ratio of Mn is greater than or equal to 20%, the
molar ratio of Ni is 40-75%, the doped
metal M is selected from at least one of Al, W, Ti, Mg, Zr, Ba and La, and the molar ratio of the doped
metal M is less than 1%. The preparation method selects a medium-
nickel low-
cobalt ternary precursor,andcomprises the following steps: 1, mixing a
lithium source,
sintering to prepare a ternary positive
electrode material with a large specific surface area and a single-
crystal-like structure, and then crushing the ternary positive
electrode material into primary monocrystal or monocrystal-like
small particles which are relatively small in particle size and are uniformly dispersed; and 2, continuously mixing the primary
small particles with a
lithium source, carrying out element M
doping,
sintering at a higher temperature, and carrying out mechanical
depolymerization to obtain the monocrystal-morphology positive
electrode material with relatively good dispersibility. According to the invention, the problems that monocrystal particles of the low-
cobalt and high-
manganese-content ternary material are difficult to grow, Li / Ni mixed arrangement is high, and the rate capability is reduced are solved.