Spherical Li[Li0.2Ni0.2Mn0.6]O2 has been synthesized by a carbonate co-precipitation method. The Li[Li0.2Ni0.2Mn0.6]O2 with a phase-pure and well-ordered layered structure was synthesized by heat-treatment of a spherical (Ni0.25Mn0.75)3O4 precursor with LiOH·H2O. The average particle size of the Li[Li0.2Ni0.2Mn0.6]O2 powders was approximately 20μm and the size distribution was quite narrow due to the homogeneity of the (Ni0.25Mn0.75)CO3. The Li[Li0.2Ni0.2Mn0.6]O2 electrode calcined at 900°C delivered an initial discharge capacity of approximately 270mAhg−1 in the voltage range of 2.0–4.6V. The differential scanning calorimetry (DSC) results for the Li[Li0.2Ni0.2Mn0.6]O2 prepared at 900°C showed a major exothermic reaction at 270°C.