Multifunctional electrochromic pseudocapacitor: integrating solar radiation control and energy storage for sustainable solutions

Pham Van Duy^1*, Phan Thi Giang¹, Yuan-Ron Ma²

¹Derpartment of Physics, Chung Yuan Christian University, Taoyuan, Taiwan
²Derpartment of Physics, National Dong Hwa University, Hualien, Taiwan

* Presenter:Pham Van Duy, email:duypham0611@cycu.edu.tw

Integrating electrochromic and energy storage functionalities into a single device is emerging as a promising research frontier. Multifunctional electrochromic devices not only block light and heat radiation from the sun but also possess energy storage capabilities, contributing to the reduction of global energy consumption. In this study, we fabricated an electrochromic pseudocapacitor based on 1D WO₃ nanorods and a 2D V₂O₅ thin film. The device consists of a WO₃ nanorod/ITO/glass as a working electrode, V₂O₅ thin film/ITO/glass as a counter electrode, and a liquid LiClO₄ electrolyte. The device exhibits remarkable tri-band electrochromic behavior across the ultraviolet, visible, and near-infrared ranges, along with impressive pseudocapacitive performance. Notably, it demonstrates large optical transmittance modulations (~47%, ~64%, and ~79%), fast switching times (~6.7 s/0.7 s, ~6.0 s/1.0 s, and ~3.0 s/0.9 s) at wavelengths of 390, 600, and 1000 nm, respectively, and excellent electrochromic stability over 5000 cycles without significant degradation. It also exhibits a high specific capacitance of ~80 F/g, an energy density of ~20 Wh/kg, and a power density of ~8779 W/kg, while maintaining outstanding pseudocapacitive stability over 10,000 cycles. This work provides valuable insights into the design of multifunctional electrochromic devices integrated with intelligent energy storage systems, offering great potential for energy-saving applications.

Keywords: VO3 nanorods, V2O5 thin film, Electrochromism, Suppercapacitor, Energy-saving application