A nanocrystalline Li[Ni0.20Li0.20Mn0.60]O-2 powder was synthesized by a simple combustion method and investigated using X-ray diffraction, scanning electron microscopy, and galvanostatic charge/discharge cycling. The particle size of the powder was distributed in the range of 100-200 nm. Rietveld analysis revealed that Li[Ni0.20Li0.20Mn0.60]O-2 is basically a layered rock-salt structure in which a small amount of Ni occupies the 3a sites. The initial discharge capacity of the Li/ Li[Ni0.20Li0.20Mn0.60]O-2 cell was about 288 mAh/g when it was cycled at a voltage range of 4.8-2.0 V with a specific current of 20 mA g(-1). A very promising factor for high-rate capability applications was a reversible capacity of 200 mAh g(-1) at the 100th cycle with a high specific current of 400 mA g(-1). The weight loss measurement for charged Li1-x[Ni0.20Li0.20Mn0.60]O-2 electrodes gave indirect evidence that the long plateau at 4.5 V did not originate from the ejection of oxygen. (C) 2003 The Electrochemical Society.