Rejuvenation of Electrochromic Devices

Abstract Electrochromic devices (ECDs) are a hot pot due to their significant energy‐saving effect in green buildings. However, the ECDs suffer from degradation induced by ion trapping during cycling, which restricts their further development. Here, it is demonstrated that the electrochromic performance of the degraded ECDs can be rejuvenated by heat treatment method The release mechanism of trapped ions in films is simulated and validated using three types of ECDs. The semi‐solid‐state ECD evinces a state of near‐failure at low temperatures can regain its initial performance by heating. All‐solid‐state ECDs, including amorphous WO 3 (a‐WO 3 ECD) and crystalline WO 3 (c‐WO 3 ECD) as the electrochromic layer, can also release the trapped ions and regain the performance (97.3% and 95.5% of initial optical modulation) by annealing, regardless of the way of degradation. The research has extended the lifespan of multiple ECDs, providing significant practical value and promoting sustainable, and eco‐friendly development.