Lithium nickel-manganese-cobalt oxide cathode powders for high voltage lithium-ion batteries

A lithium metal oxide powder for a cathode material in a rechargeable battery, comprising a core and a surface layer, the surface layer being delimited by an outer and an inner interface, the inner interface being in contact with the core, the cathode material having a layered crystal structure comprising the elements Li, M and oxygen, wherein M has the formula M=(Niz (Ni1/2 Mn1/2)y Cox)1-k Ak, with 0.15≤x<0.20, 0.40≤z≤0.55, x+y+z=1 and 0<k≤0.1, wherein x, y, z, and k are measured by ICP;

• wherein the Li content is stoichiometrically controlled with a molar ratio 1.00≤Li:M≤1.10;
• wherein A is at least one dopant and comprises Al and one or more elements selected from the group consisting of Ca, Zr, W, Cr, and V, wherein the core at the inner interface has an Al content of 0.3-3 mol %;
• wherein the surface layer comprises an intimate mixture of Ni, Co, Mn, LiF and Al2O3 determined by XPS;
• and wherein the surface layer has a Mn content that decreases from the Mn content at the inner interface, to less than 50% of the Mn content at the outer interface, wherein Mn contents at the inner and outer interfaces are measured by XPS depth profile.