Electrochromic devices (ECD) have become a hot research topic in the field of green buildings due to their excellent energy efficiency and thermal management capabilities. Currently, challenges such as difficulties in large-area preparation, high costs, and degradation of electrochromic performance over time have hindered their widespread application. A strategy incorporating a dual-phase nanocrystalline structure of WO 3 and TiO 2 ·H 2 O is proposed, in which specific synthesis parameters are precisely controlled to tailor the microstructure and composition of the films, enabling the fabrication of large-area WO 3 -PB ECD with UV-rejuvenation electrochromic performance. As a result, the as-prepared WO 3 -PB ECD exhibits an optical modulation of 75.6% and a remarkable cycle life exceeding 13,000 cycles. The electrochromic performance degradation caused by long cycles can be restored via UV irradiation. Utilizing UV light to restore the performance of these WO 3 -PB ECDs promotes sustainable and environmentally friendly development, highlighting their important practical value.
Kun Wang,Hongliang Zhang,Guoxin Chen,Tian Tian,Kai Tao,Lingyan Liang,Junhua Gao,Hongtao Cao
The complementary electrochromic devices based on WO 3 and Prussian blue electrodes (PB) have shown a limited chemical stability and durability because WO 3 is degraded in electrochromic performance and PB is gradually dissolved in the Li + -based electrolyte under neutral pH conditions. Herein, the utilization of acetic acid as super-additive solution was proposed to improve WO 3 cathodes and stabilize PB anodes, in which the highly nanoporous nanocrystal-in-glass WO 3 and hierarchical PB was made by electron beam evaporation and electrochemical deposition method, respectively. Our findings suggest that synergistic effects of Li + and H + on WO 3 and Prussian blue electrodes contribute to the improvement on electrochemical, electrochromic, and cycling stability performance of the whole device. Impressively, the WO 3 -PB complementary electrochromic device could experience a superior long-term cycling stability of over 10,000 cycles, with a high coloration efficiency of 137.80 cm 2 C −1 and a maximum transmittance modulation of 66.22%@ 633 nm. All these results open a new way to the construction of high-performance electrochromic devices.