Layered Li[Li0.1Ni0.35Mn0.55]O-2 powder was synthesized using a sol-gel method. The Li[Li0.1Ni0.35Mn0.55]O-2 electrode delivered stable capacity of 180-200 mAh/g depending on the calcination temperature with excellent capacity retention when cycled between 2.5 and 4.6 V. Transmission electron microscopy of the as-prepared powder showed that the material consisted of O3-layered particles with a high degree of the stacking disorder, mixed with cubic phases. The prepared Li[Li0.1Ni0.35Mn0.55]O-2 electrodes were structurally stable against the electrochemical cycling although there were subtle differences in both electrochemical properties and structural stability depending on the calcination temperature. (C) 2003 The Electrochemical Society.