A carbonate co-precipitation method was employed to prepare spherical Li[Ni1/3Co1/3Mn1/3]O-2 cathode material. The precursor, [Ni1/3Co1/3Mn1/3]CO3, was prepared using ammonia as chelating agent under CO2 atmosphere. The spherical Li[Ni1/3Co1/3Mn1/3]O-2 was prepared by mixing the precalcined [Ni1/3Co1/3Mn1/3] CO3 with LiOH followed by high temperature calcination. The preparation conditions such as ammonia concentration, co-precipitation temperature, calcination temperature and Li[Ni1/3Co1/3Mn1/3] ratio were varied to optimize the physical and electrochemical properties of the prepared Li[Ni1/3Co1/3Mn1/3]O-2. The structural, morphological, and electrochemical properties of the prepared LiNi1/3Co1/3Mn1/3O2 were characterized by XRD, SEM, and galvanostatic charge-discharge cycling. The optimized material has a spherical particle shape and a well ordered layered structure, and it also has an initial discharge capacity of 162.7 mAh g(-1) in a voltage range of 2.8-4.3 V and a capacity retention of 94.8% after a hundred cycles. The optimized ammonia concentration, co-precipitation temperature, calcination temperature, and Li/[Ni1/3Co1/3Mn1/3] ratio are 0.3 mol L-1, 60 degrees C, 850 degrees C, and 1.10, respectively. (C) 2009 Elsevier B.V. All rights reserved.