High-Performance Electro-optical Dual-Mode Color-Changing and Energy Storage Device Based on Mo-Doped WO₃ and TiO₂/NiO Thin Films

Under optical and electrical control, a multifunctional electro-optical dual-control color-changing and energy storage device not only realizes fast color conversion but also achieves good energy storage performance. In this work, Mo-doped WO₃ (Mo-WO₃) films were prepared by a one-step hydrothermal method, among which the 2 at. % Mo-doped WO₃ film has the best electrochromic and energy storage performance. Meanwhile, TiO₂/NiO composite films were prepared by the hydrothermal method and electrodeposition method. The TiO₂/NiO/N719 photoanode was prepared by the dip-dyeing method on the TiO₂/NiO composite film. The results show that the TiO₂/NiO-10s/N719 composite film has excellent photoelectric conversion and energy storage properties. Finally, choosing Mo-WO₃ as the cathode and the TiO₂/NiO/N719 film as the anode, a multifunctional electro-optical dual-control Mo-WO₃@TiO₂/NiO/N719 color-changing and energy storage device was constructed. Under electrical control, it shows a fast color switching rate (the coloring/bleaching time is 4.1/2.9 s), excellent coloration efficiency (62.1 cm²/C), obviously improved area capacitance (90.4 mF/cm²), and excellent cycle stability. Under optical control, it shows a shortened optical response time (the coloring/bleaching is 70.3/158.9 s), excellent coloration efficiency (58.2 cm²/C), better area capacitance (51.1 mF/cm²), and excellent photoelectric conversion efficiency.