Positive electrode material, preparation method thereof and secondary lithium battery

The invention provides a positive electrode material, a preparation method thereof and a secondary lithium battery. The positive electrode material is characterized in that the chemical general formula of the positive electrode material is LibNi1-x-yCoxAlyMzO2, b is more than or equal to 0.95 and less than or equal to 1.10, x is more than or equal to 0 and less than or equal to 0.15, y is more than or equal to 0.01 and less than or equal to 0.1, z is more than 0 and less than or equal to 0.05, and the element M is a metal element; M elements are distributed inside and on the surface layer of the positive electrode material, the M elements distributed inside the positive electrode material exist in a doping form, and the M elements distributed on the surface layer of the positive electrode material exist in a coating layer form formed by M oxide and/or lithium M composite oxide; and the molar ratio of the internal M element to the surface layer M element is greater than 0.5. The positive ...