Multi-element positive electrode material and preparation method thereof

The invention belongs to the technical field of lithium ion battery electrode materials, and discloses a multi-element positive electrode material and a preparation method thereof. The multi-element positive electrode material is a secondary particle composed of primary particles, and a metal oxide modified layer containing lithium and N exists on the surface of the secondary particle; an N element gradient doped layered structure exists at the grain boundary of the surface of the primary particle, and the content of the N element is gradually reduced from the surface of the primary particle to the inside, so that negative gradient doping is formed. The metal oxide modification layer containing lithium and N reduces the contact area between the multi-element positive electrode material and an electrolyte, the N element gradient doping layered structure improves the interface stability, the lithium-nickel mixed arrangement degree is reduced, and the cycling stability of the material is improved. According to t