Interest in vanadium pentoxide (V205) as an electrochromic material has increased with the realization that V205 has suitable properties for counter electrode applications in variable transmittance electrochromic devices. Vari- able transmittance devices require a charge balancing counter electrode whose optical properties either contribute to, or at least do not interfere with, the overall transmittance modulation. Preliminary studies have shown that V205 exhibits anodic coloration in the blue and near-UV for lithium intercalation/deintercalation and is thus a suitable counter electrode to cathodically coloring electrochromic materials such as tungsten trioxide (W03).
Stuart F. Cogan, Stuart F. Cogan,
"Electrochromic vanadium pentoxide", Proc. SPIE 10304, Large-Area Chromogenics: Materials and Devices for Transmittance Control, 103040K (28 March 1990); doi: 10.1117/12.2283623; https://doi.org/10.1117/12.2283623