A positive electrode active material suitable for lithium-ion rechargeable batteries, said positive electrode active material comprising Li, M', and oxygen, wherein M' comprises: - Ni in a content x between 75.0 mol% and 95.0 mol%, relative to M', - Co in a content y between 1.0 mol% and 25.0 mol%, relative to M', - Mn in a content z between 0.0 mol% and 25.0 mol%, relative to M', - Al in a content b between 0.0 mol% and 5.0 mol%, relative to M', - Element other than Li, Ni, Mn, Co, O and Al in a content a between 0.0 mol% and 5.0 mol%, relative to M', - wherein x, y, z, a and b contents are measured by ICP, - wherein x+y+z+a+b is 100.0 mol%, wherein said positive electrode active material comprises secondary particles comprising a plurality of primary particles, wherein the positive electrode active material has a Ni content Ni edge and Co content Co edge as measured by cross-sectional EDS (CS-EDS) at the edge of the secondary particle of the positive electrode active material, wherein Ni and Co contents are expressed as mol% relative to the sum of Ni, Mn, and Co content as measured by CS-EDS at the edge of the secondary particle of the positive electrode active material, wherein the positive electrode active material has a Ni content Ni center and Co content CO center measured by CS-EDS at the center of the secondary particle of the positive electrode active material, wherein Ni and Co contents are expressed as mol% relative to the sum of Ni, Mn, and Co content as measured by CS- EDS at the center of the secondary particle of the positive electrode active material, wherein the ratio Ni edge / Ni center < 0.98, wherein the ratio Co edge / CO center > 1.10, wherein said secondary particles have an average crystallite size of at least 15 nm and at most 40 nm, as determined by XRD. - Ni in a content x between 75.0 mol% and 95.0 mol%, relative to M', - Co in a content y between 1.0 mol% and 25.0 mol%, relative to M', - Mn in a content z between 0.0 mol% and 25.0 mol%, relative to M', - Al in a content b between 0.0 mol% and 5.0 mol%, relative to M', - Element other than Li, Ni, Mn, Co, O and Al in a content a between 0.0 mol% and 5.0 mol%, relative to M', - wherein x, y, z, a and b contents are measured by ICP, - wherein x+y+z+a+b is 100.0 mol%, wherein said positive electrode active material comprises secondary particles comprising a plurality of primary particles, wherein the positive electrode active material has a Ni content Ni edge and Co content Co edge as measured by cross-sectional EDS (CS-EDS) at the edge of the secondary particle of the positive electrode active material, wherein Ni and Co contents are expressed as mol% relative to the sum of Ni, Mn, and Co content as measured by CS-EDS at the edge of the secondary particle of the positive electrode active material, wherein the positive electrode active material has a Ni content Ni center and Co content CO center measured by CS-EDS at the center of the secondary particle of the positive electrode active material, wherein Ni and Co contents are expressed as mol% relative to the sum of Ni, Mn, and Co content as measured by CS- EDS at the center of the secondary particle of the positive electrode active material, wherein the ratio Ni edge / Ni center < 0.98, wherein the ratio Co edge / CO center > 1.10, wherein said secondary particles have an average crystallite size of at least 15 nm and at most 40 nm, as determined by XRD.