Preparation of WO3 gel electrochromic device by simple two-step method

Gel electrochromic devices (gel ECDs) have promising application prospects in smart windows due to their energy-saving effects and superior electrochromic performance. However, the rapid preparation of gel electrolytes is one of the reasons limiting the further promotion of gel ECDs. In this work, we proposed a simple doctor blade method to prepare PVDF gel electrolytes with high ionic conductivity (3.7 * 10 −3 S cm −1 ) and excellent mechanical properties (268% strain), accompanied by high transmittance (exceeding 95% within 600–1100 nm). And we also prepared WO 3 gel ECDs by using PVDF gel electrolytes as electrolyte layer. Compared with liquid ECDs, WO 3 gel ECDs' lifetime has increased by 33%, mainly due to the increased oxidation potential with PVDF gel electrolyte addition, enhancing oxidation resistance . In addition, the large-area flexible gel ECDs (6 * 10 cm 2 ) were assembled, which provides practical guidance for preparing large-area flexible gel ECDs in the future.