Electrochemical properties of 0.6Li₂MnO₃-0.4Li(Ni_1/3Mn_1/3Co_1/3)O₂ composite cathode powders with spherical shape and fine size

0.6Li₂MnO₃-0.4Li(Ni_1/3Mn_1/3Co_1/3)O₂ composite cathode powders are prepared by spray pyrolysis. The spherical shape of the precursor powders are maintained after post-treatment at temperatures between 600 and 900°C. The grain growth in the powders increases with increasing post-treatment temperatures. The BET surface area of the composite cathode powderspost-treated at 800°C is 7 mg² g^-1. The discharge capacity of the cathode powders post-treated at 800°C decreases from 274 mAh gg^-1 to 242 mAh gg^-1 by the 50th cycle, the capacity retention being 88.3%. However, the discharge capacity of the powders post-treated at 700°C decreases from 247 mAh g_-1 to 201 mAh gg^-1 by the 9th cycle. A high amount of Li₂MnO₂ in composite powders post-treated at high temperatures improves their cycle properties even at a high cutoff voltage of 4.8 V.