Process for making a coated cathode active material

A process for making an electrode active material according to general formula Li1+x(TM1-yM1y)1-xO2, wherein TM is a combination of metals according to general formula (I),

• (NiaCobMnc)1-dM2d (1)
• wherein
• a is in a range of from 0.6 to 0.99,
• b is in a range of from 0.005 to 0.2,
• c is in a range of from 0.005 to 0.2, and
• d is in a range of from zero to 0.1,
• M2 is at least one of Al, Mg, W, Ti, and Zr,
• a+b+c=1,
• x is in a range of from zero to 0.2, M1 is selected from the group consisting of Nb and Ta, and y is in a range of from 0.001 to less than 0.01, said process comprising the following steps:
• (a) mixing
• (A) a particulate mixed oxide or (oxy)hydroxide of Mn, Co and Ni, and
• (B) at least one lithium compound selected from the group consisting of lithium hydroxide, lithium oxide and lithium carbonate, and
• (C) an amorphous compound of Nb or Ta, and
• (b) subjecting said mixture to heat treatment at a temperature in a range of from 700 to 1000° C.,
• wherein at least 60 mole-% of a transition metal of TM is Ni.