This disclosure provides a positive electrode active lithium-excess metal oxide with composition LixMyO2 (0.6≤ y ≤ 0.85 and 0 ≤ x + y ≤ 2) for a lithium secondary battery with a high reversible capacity that is insensitive with respect to cation-disorder. The material exhibits a high capacity without the requirement of overcharge during the first cycles.
