Zn Anode-Based Electrochromic Devices: Progress & Challenges

Unlike conventional electrochromic devices, Zinc anode-based electrochromic devices (ZECDs) ensure excellent charge balance between the electrochromic layer and Zn anode during the coloring/bleaching by reversible metal deposition/stripping on the Zn anode. Meanwhile, the inherent potential difference between the metal anode and the electrochromic layer can drive the spontaneous coloration/bleaching of ZECDs, featuring energy retrieval functionality. This review discusses the working mechanisms, performance indexes of ZECDs, and the impact of material selection on ZECD performance. Furthermore, we comprehensively summarize the latest research progress of ZECDs in energy storage, smart windows, and multicolor displays. We argue that using high-transparency zinc mesh, additive manufacturing processes, and self-healing electrochromic materials can significantly advance the commercialization of large-area ZECDs. Finally, “electrode-free” device structures, renewable or replaceable electrolytes, and strategies to suppress zinc dendrites are prospected to overcome cost-effectiveness and lifespan issues of ZECDs. This review aims at enabling more efficient and advanced ZECDs for multifunctional applications.