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.

Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages, which have shown great potential applications including smart windows, non-emissive displays, optical filters, among others. Although the current rigid electrochromic devices have shown emerging interest and developed rapidly, many applications (e.g., wearable/deformable optoelectronics) are blocked due to their inflexible features. Herein, the adaption of rigid electrochromic devices to flexible ones is of particular interest for the new era of smart optoelectronics. In this review, the current state-of-the-art achievements of flexible electrochromic devices (FECDs) are highlighted, along with their design strategies and the choice of electrochromic materials. The recent research progress of FECDs is reviewed in detail, and the challenges and corresponding solutions for real-world applications of FECDs are discussed. Furthermore, we summarize the basic fabrication strategies of FECDs and their potential applications. In addition, the development trend, the perspectives, and the outlook of FECDs are discussed at the end of this Review, which may provide recommendations and potential directions to advance the practical applications of FECDs.