LiFe(1-x)CoxPO(4) (0 <= x <= 1.0) solid solutions were prepared by solid-state reactions. X-ray diffraction and X-ray photoelectron spectroscopy were employed to analyze the variation of their structures and the chemical environments around the P and O atoms of the solid solution with various Co contents. The electrochemical performance of LiFe1-xCoxPO4 was also comparatively studied with cyclic voltammetry, and galvanostatic charge-discharge. (c) 2005 Elsevier B.V. All rights reserved.