A Novel Method for Performance Rejuvenation of WO₃//NiO Electrochromic Devices: Lithium Ion Kinetic Behavior with Variable Cycling Temperature and Switching Voltage

Electrochromic devices (ECDs) have great potential in energy efficient buildings, which may suffer from electrolyte ionic-trapping-caused invalidation of optical transmittance and charge capacity, though research is lacking on the migration regularity of electrolyte ions and the mechanism of performance recovery. In this paper, we investigate the combined effects of the cycling temperature and switching voltage on WO₃//NiO solid-state devices. The relationship of temperature-voltage-Li⁺ concentration of ECDs is supposed to be established by exploring the activation and energy barrier for Li⁺ migration during the electrochromic process, providing quantitative information to optimize factors such as charge capacity, coloring efficiency, and lifetime, hence obtaining a novel strategy for ECDs performance recovery. Here we demonstrate that degraded ECDs can be rejuvenated by continuous cycling at 50 °C with the switching voltage of −1.4 V/ +1.4 V, thus regaining their initial electrochromic performance.