Improved stability of electrochromic devices using Ti-doped V2O5 film

Vanadium pentoxide (V2O5) is a promising material for constructing electrochromic devices, due to its outstanding properties of lithium ion intercalation/deintercalation. However, its poor cyclic stability limits practical applications. We report here that V2O5 films gain significantly improved cyclic stability by doping with titanium (Ti) and perform well in WO3-based electrochromic devices. V2O5 films were fabricated by spin coating with a vanadium triisopropoxy oxide solution followed by heat treatment. Xray diffraction studies reveal that introducing the Ti element reduces the crystallinity of a V2O5 film and distorts its layer structure. The cyclic stability of the V2O5 films increases as the doped Ti content increases. The electrochromic device assembled with an optimized V2O5 electrode (V: Ti = 2: 1) has lasted 200,000 cyclic switching times between the lowest (2%) and highest (62%) transmittance with no significant degradation of performance. (C) 2015 Elsevier Ltd. All rights reserved.