Integrating Transparent Zinc Mesh and Anti-Freezing Hydrogel Electrolyte Toward Durable Zinc Anode-Based Electrochromic Devices

Emerging zinc-anode-based electrochromic devices (ZECDs) significantly contribute to displays or smart windows. However, the majority of existing ZECDs employ opaque zinc sheets and liquid electrolytes, posing key limitations of restricted light transmission capacity, possible electrolyte leakage, and poor frost resistance, while the issue of zinc dendrites is also overlooked in ZECDs. Here, a flexible and transparent zinc mesh is developed for the zinc-anode-based electrochromic device (ZECD). The effect of zinc dendrites on the cycling process of ZECDs is investigated by controlling different zinc deposition morphologies. Additionally, a hydrogel electrolyte suitable for the ZECD smart window has been developed with excellent frost resistance, water-retention capability, and electrical conductivity. Finally, the ZECD smart window is assembled based on the transparent zinc mesh and the hydrogel electrolyte. The window has excellent cyclic stability (94.4% retention after 1000 cycles), high optical contrast (78.7% at 633 nm), and high energy-recovery efficiency (61.6%). It is foreseeable that these results will provide a boost to the future development of ZECDs and energy efficiency in buildings.