Enhanced electrochromic and energy storage performance in mesoporous WO3 film and its application in a bi-functional smart window

Abstract

Construction of multifunctional photoelectrochemical energy devices is of great importance to energy saving. In this study, we have successfully prepared a mesoporous WO₃ film on FTO glass via a facile dip-coating sol–gel method; the designed mesoporous WO₃ film exhibited advantages including high transparency, good adhesion and high porosity. Also, multifunctional integrated energy storage and optical modulation ability are simultaneously achieved by the mesoporous WO₃ film. Impressively, the mesoporous WO₃ film exhibits a noticeable electrochromic energy storage performance with a large optical modulation up to 75.6% at 633 nm, accompanied by energy storage with a specific capacity of 75.3 mA h g⁻¹. Furthermore, a full electrochromic energy storage window assembled with the mesoporous WO₃ anode and PANI nanoparticle cathode is demonstrated with large optical modulation and good long-term stability. Our research provides a new route to realize the coincident utilization of optical-electrochemical energy.