The first charge and discharge reaction of LiCoVO4 with a spinel structure as an anode material for a Li-ion battery was investigated. LiCoVO4 showed a much larger reversible capacity, about 685 Ah kg-1, compared with a commercially available graphite anode. From the X-ray diffraction measurement, the spinel structure of LiCoVO4 where V ions reside in a tetrahedral site initially changed to an atacamite-type structure where V ions occupied an octahedral site and finally showed irreversible deformation to an amorphous structure during the first Li insertion/removal reaction. The results of X-ray absorption spectroscopy analysis revealed that the oxidation state and the coordination environmental structure of V ions varied reversibly in the first cycle process. (C) 2003 The Electrochemical Society. All rights reserved.