Positive electrode material and preparation method thereof

The invention provides a positive electrode material and a preparation method thereof. The chemical formula of the positive electrode material is LiFe < 1-a > (Ni < x > Co < y > Mn < z >) < a > PO4/C, wherein a is more than or equal to 0.002 and less than or equal to 0.05, 0 lt; xlt; 1, 0lt; yt; Yt; 1, 0lt; zlt, zlt; x + y + z = 1. Ternary metal (Ni < x > Co < y > Mn < z >) in the nickel-cobalt-manganese ternary precursor material is doped into lithium iron phosphate in a cation form through high-temperature sintering to replace the Fe element position, so that the ionic conductivity of the material is greatly improved, and the migration rate of ions in the material is improved; meanwhile, an organic carbon source is deposited on the surface of the material and pyrolyzed and carbonized at high temperature to obtain amorphous carbon, namely a coating layer, so that the electronic conductivity of the material is improved; according to the invention, through surface carbon layer coating and composite phase catio