In this paper, Cu/V oxide thin films were prepared by reactive d.c./r.f. co-sputtering. Nanostructured films were obtained and their composition and crystallinity were investigated. The electrochemical behavior of the thin film electrodes was studied, in order to evaluate their performance as cathodes in miniaturized systems. The behavior of the mixed oxide films and the pure vanadium pentoxide in thin film form are compared. All films presented a high insertion capacity in the first cycle. The film with composition CU4.0VO5.5 presented the highest capacity and stability in comparison with all the other films. (c) 2006 Elsevier Ltd. All rights reserved.