Abstract: Process for making a partially coated electrode active material wherein said process comprises the following steps: (a) Providing an electrode active material according to general formula Li1+xTM1-xO2, wherein TM is Ni and, optionally, at least one of Co and Mn, and, optionally, at least one element selected from Al, Mg, and Ba, transition metals other than Ni, Co, and Mn, and x is in the range of from zero to 0.2, wherein at least 50 mole-% of the transition metal of TM is Ni, (b) treating said electrode active material with an aqueous medium, (c) partially removing water by solid-liquid separation method, (d) treating the solid residue with an aqueous formulation of at least one heteropolyacid or its respective ammonium or lithium salt, (e) treating the residue thermally.