Cobalt-free positive electrode material, preparation method thereof, positive electrode sheet and battery

Abstract

This invention relates to the field of battery technology, specifically to a cobalt-free cathode material, its preparation method, a cathode sheet, and a battery. The provided cobalt-free cathode material has the general chemical formula Li. a Ni x Mg y Al z O2·nB; where 0.9≤a≤1.1, 0<n≤0.1, 0<x<1, 0<y<1, 0<z<1, 1≤x+y+z≤1.2; the cobalt-free cathode material has a core-shell structure, and the chemical formula of the core of the cobalt-free cathode material is Li a Ni x Mg y Al z O2, wherein Mg is an element that dops and substitutes for Li at alkali metal sites, and Al is an element that dops and substitutes for Ni at transition metal sites; a coating layer is formed on the surface of the core, and the coating layer contains element B. This invention can improve the structural stability of cobalt-free cathode materials, alleviate the problem of poor structural stability in existing cobalt-free cathode materials, effectively suppress phase changes, prevent secondary particle cracking, reduce electrolyte corrosion, and facilitate further expansion of the application range of cobalt-free cathode materials.

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