Phase pure Li0.95Na0.05Ni1/3Co1/3Mn1/3O2 and LiNi1/3Co1/3Mn1/3O2 have been synthesized by calcination of co-precipitated precursors. Scanning electron microscopy shows that the powders are aggregated microplates sized between 100 nm and 300 nm in diameter and 50 nm in thickness. Electrochemical tests show that the Li0.95Na0.05Ni1/3Co1/3Mn1/3O2 discharges initially a much higher capacity under a current density of 27 mA g−1 (250.5 mAh g−1) than LiNi1/3Co1/3Mn1/3O2 (155.4 mAh g−1). The discharge capacity at the 70th cycle is 134.8 mAh g−1 under a current density of 135 mA g−1, and it increases to 143.1 mAh g−1 after the test cell has been standing still for 3 months. The latter cell exhibits better cycle performance with capacity retention of 99.02% after 110 cycles at different current densities, therefore, Li0.95Na0.05Ni1/3Co1/3Mn1/3O2 is capable of self-repairing.