A lithium cobalt-based oxide cathode active material powder comprising particles having a median particle size D50 of greater than or equal to 20 μm, preferably 25 μm, and less than or equal to 45 μm, said particles having an averaged circularity of greater than or equal to 0.85 and less than or equal to 1.00, said particles having a general formula Li1+aCo1-x-y-zAlxM′yMezO2, wherein M′ and Me comprise at least one element of the group consisting of: Ni, Mn, Nb, Ti, W, Zr, and Mg, with −0.01≤a≤0.01, 0.002≤x≤0.050, 0≤y≤0.020 and 0≤z≤0.050, said lithium cobalt-based oxide particles having a R-3m structure and (018) diffraction peak asymmetry factor AD(018) of greater than or equal to 0.85 and less than or equal to 1.15, said diffraction peak asymmetry factor being obtained by a synchrotron XRD spectrum analysis with an emission wavelength λ value equal to 0.825 Å.