Preparation method of surface-modified positive electrode material

The invention relates to the technical field of lithium ion batteries, and discloses a preparation method of a surface-modified positive electrode material, which comprises the following steps: weighing a nickel source, a cobalt source and a manganese source according to the required stoichiometric ratio, and dissolving in water to obtain a uniformly mixed precursor solution; the lithium-rich manganese-based layered positive electrode material is prepared into a positive electrode, surface oxygen defects and local lattice distortion are formed under the induction of the surface modifier, the electrochemical performance of the lithium-rich manganese-based positive electrode material is improved, the surface modifier is thermally decomposed to generate a reducing atmosphere under a high-temperature calcination condition, and the surface of the lithium-rich manganese-based layered positive electrode material is reduced under the influence of the reducing atmosphere. Lattice oxygen on the surface of the lithium-r