Lithium non-stoichiometric Li[Li-x(Ni1/3Co1/3Mn1/3)(1-x)]O-2 materials (0 <= x <= 0.17) were synthesized using a spray drying method. The electrochemical properties and structural stabilities of the synthesized materials were investigated. The synthesized materials exhibited a hexagonal structure in all the x-value and the lattice parameters of the materials were gradually decreased with increasing x-value due to an increasing amount of W, ions for charge compensation. The capacity retention ability and rate capability of the stoichiometric Li(Ni1/3Co1/3Mn1/3)O-2 material were improved by increasing x-value, the so-called overlithiation. We found that the overlithiated materials could keep more structural integrity than the stoichiometric one during electrochemical cyclings, which could be one of reasons for a better electrochemical properties of the overlithiated materials. (c) 2007 Elsevier B.V. All rights reserved.