We studied electrochromic cells incorporating evaporated WO3, MoO3 and mixed WO3-MoO3 thin films as electrochromic layers. Li+ doped V2O5 films served as an ion storage layer. The devices exhibit good optical properties with very low luminous transmittance values in the colored state, which make them suitable for large-area window applications. Addition of V2O5 films as an ion storage layer was found to improve the cell coloration performance up to 74%.