Preparation method of ultrahigh-nickel high-cycle cobalt-free positive electrode material

The invention discloses a preparation method of an ultrahigh-nickel high-cycle cobalt-free positive electrode material, which comprises the following steps: S1, preparing a nickel source, a manganese source, a complexing agent and a precipitant into a reaction solution for coprecipitation reaction to obtain slurry; and centrifuging, washing and drying to obtain the nickel-manganese hydroxide. S2, nickel manganese hydroxide, a lithium source and a doping agent are evenly mixed to obtain a mixture, the mixture is sintered for the first time, the oxygen concentration in the sintering atmosphere is 86%-88%, and the sintering temperature is 650-800 DEG C; and S3, the sintered material is smashed, subjected to acid pickling and dried. And S4, uniformly mixing the dried material with a coating agent, and carrying out second sintering. The positive ion mixed arrangement of the material is adjusted and controlled at a certain positive ion mixed arrangement degree, and the internal and external lattice distortion is re