Nanometer-sized 0.6Li 2 MnO 3 ·0.4LiNi 0.5 Mn 0.5 O 2 composite cathode powders are prepared directly by high-temperature flame spray pyrolysis. The precursor powders and the powders post-treated at 800°C exhibit mixed-layered crystal structures comprising layered Li 2 MnO 3 and layered LiNi 0.5 Mn 0.5 O 2 phases. The discharge capacity of the precursor powders decreased from 193mAhg −1 to 96mAhg −1 by the 9th cycle, corresponding to a capacity retention of 49.7%. Post-treatment at 800°C increases the capacity retention of the post-treated composite powders to 94.6% after 50 cycles, corresponding to a decrease in the discharge capacity from 225 to 213mAhg −1 . The post-treated composite powders that contain a high amount of the Li 2 MnO 3 phase have a high initial discharge capacity and good cyclability.