Ultrahigh nickel single crystal ternary positive electrode material with cobalt-doped surface, preparation method thereof and lithium ion battery

The invention belongs to the field of lithium ion batteries, and discloses a preparation method of a surface cobalt-doped ultrahigh nickel single crystal ternary positive electrode material, and the method specifically comprises the following steps: step 1, crushing a nickel-manganese binary precursor into small particles with the specifications of D50: 2-7 [mu] m and Dmin: 0.1-0.3 [mu] m; 2, etching and coating the small particles by adopting a solution containing one of oxalic acid and hydrochloric acid and hydroxyl cobalt oxide, controlling the pH value of the solution to be 4-6, and then drying to form a nickel-manganese binary precursor; and 3, mixing and sintering the small-particle nickel-manganese binary precursor obtained in the step 2 and a lithium source to obtain the ultrahigh nickel single crystal ternary positive electrode material doped with cobalt on the surface. According to the ultrahigh nickel single crystal ternary positive electrode material, through optimization of the particle size of a