Abstract: A positive electrode active material powder suitable for lithium-ion batteries, comprising lithium transition metal-based oxide particles comprising a core and a surface layer, said surface layer being on top of said core, said particles comprising the elements: Li, a metal M? and oxygen, wherein the metal M? has a formula: M?(NizMnyCox)1?kAk, wherein A is a dopant, 0.55?z?0.89, 0.05?y?0.25, 0.05?x?0.25, x+y+z+k=1, and k?0.01, said positive electrode active material powder having a mean particle size D50 ranging from 3 ?m to 15 ?m and a surface layer thickness ranging from 5 nm to 200 nm. The surface layer comprises aluminum in a content superior or equal to 0.04 wt % and inferior or equal to 0.15 wt % relative to the total weight of the positive electrode active material.