Abstract: Spectroscopic and electrochemical properties of amorphous V2O5 films, prepared by r.f. sputter deposition, were compared before and after electrochemical lithium intercalation. The films gave a cyclic voltammogram typical of vanadium pentoxide with two/three steps of reversible electrochromism (yellow-green-blue). The expected effect of lithiation on chemical state and surface composition was monitored using XPS. A careful curve-fitting procedure of the detailed spectra was adopted and the in-depth profile analysis of the intercalated films clearly showed their surface reorganization as a function of time and ultrahigh vacuum conditions. The first objective of this work was to establish the influence of lithium intercalation while minimising degradation effects due to its high reactivity with the atmosphere, taking advantage of the in situ sample transfer facility. Copyright (C) 2003 John Wiley Sons, Ltd.