Sodium-ion battery positive electrode material and preparation method thereof

The chemical formula of the sodium ion battery positive electrode material is NanNixMnyTizM1-x-y-z, n is larger than or equal to 0.55 and smaller than or equal to 0.87, x is larger than or equal to 0.1 and smaller than or equal to 0.4, y is larger than or equal to 0.3 and smaller than or equal to 0.7, z is larger than or equal to 0.1 and smaller than or equal to 0.4, and M is any one of La, Ce and Y; the positive electrode material has a composite phase layered structure composed of P2 and O3 phases. The preparation method of the material comprises the steps that a sodium source, metal manganese powder, nickel oxide, titanium oxide and rare earth oxide are weighed according to the molar ratio of all elements in the chemical formula NanNixMnyTizM (1-x-y-z) O2, the sodium source is excessive by 2%-5%, dry ball milling is conducted for 5-20 h after mixing, and a precursor is obtained; and calcining the precursor at the temperature of 350-600 DEG C for 5-10 hours, and then calcining at the temperature of 800-1000