Positive electrode material, preparation method thereof and lithium ion battery

The invention relates to a positive electrode material, a preparation method thereof and a lithium ion battery, the positive electrode material comprises a base material and a coating layer located on at least part of the surface of the base material, and the coating layer comprises a carbon material; the chemical general formula of the base material is LiaNixCoyAlzMbO2, a is greater than or equal to 0.99 and less than or equal to 1.05, x is greater than or equal to 0.85 and less than or equal to 0.95, y is greater than 0.05 and less than 0.15, y is greater than 0 and less than or equal to 0.1, x + y + z = 1, b is greater than or equal to 0 and less than 0.04, and M is a metal element; wherein the mass ratio of LiOH to Li2CO3 in the positive electrode material is (0.25 to 0.6): 1. The positive electrode material can effectively reduce the residual alkali content on the surface of the material, reduce the impedance on the surface of the positive electrode material, and improve the cycle performance and the the