LITHIUM NICKEL-BASED COMPOSITE OXIDE AS A POSITIVE ELECTRODE ACTIVE MATERIAL FOR RECHARGEABLE LITHIUM-ION BATTERIES

The present invention provides a positive electrode active material for lithium-ion rechargeable batteries, wherein the positive electrode active material comprises Li, M′, and oxygen, wherein M′ comprises:Ni in a content x between 60.0 mol % and 95.0 mol %, relative to M′;Co in a content y, wherein 0≤y≤40.0 mol %, relative to M′;Mn in a content z, wherein 0≤z≤70.0 mol %, relative to M′;D in a content a, wherein 0≤a≤2.0 mol %, relative to M′, wherein D comprises an element other than Li, O, Ni, Co, Mn, F, W and S;F in a content b, wherein b>0, preferably b is between 0.1 mol % and 4.0 mol %, relative to M′;W in a content c, wherein c>0, preferably 0.01≤c≤4.0 mol %, relative to M′;S in a content d, wherein d>0, preferably between 0.01 mol % and 3.0 mol %, relative to M′; and,B in a content e, wherein 0≤e≤4.0 mol %, relative to M′; and,wherein x, y, z, a, c, and d are measured by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES),wherein b is measured by Ion chromatography (IC),wherein x+y+z+a+b+c+d is 100.0 mol %,wherein the positive electrode active material has a F content FA defined asb(x+y+z+b+c+d),W content WA defined asc(x+y+z+b+c+d),and S content SA defined asd(x+y+z+b+c+d),wherein the positive electrode active material has a F content FB, W content WB, and S content SB wherein FB, WB, and SB are determined by X-ray photoelectron spectroscopy (XPS) analysis, wherein FB, WB, and SB are each expressed as molar fraction compared to the sum of molar fractions of Co, Mn, Ni, F, W and S as measured by XPS analysis,wherein the ratio FB/FA>1.0,wherein the ratio WB/WA>1.0, andwherein the ratio SB/SA>1.0.