The birth of zinc anode-based electrochromic devices

Since the discovery of electrochemical coloration phenomenon, electrochromic devices capable of monitoring transmittance, reflectance, and absorption at designated wavelengths have embraced great achievements. The marriage of electrochemistry and optical modulation has infused fascinating properties in electrochromic devices, which find applications in thermal management, display, smart windows, and camouflage. Inspired by the multipronged advancements in electrochemical devices, the incorporation of multivalent metal ions having rich electrochemistry into electrochromic devices is bloomed in recent years. Zinc, distinguished by its high crustal abundance, suitable standard redox potential, and inherent safety, has facilitated the assembly of highly efficient electrochromic devices. Zinc anode-based electrochromic devices with dual-band (visible and near-infrared) tunability, energy retrieval functions, multi-color options, multiple working modes (transmittance mode and reflectance mode), and scalability have been prominently showcased. Here in this review, the birth of zinc anode-based electrochromic devices will be systematically narrated, starting from the discovery of electrochromic phenomenon, to the evolution of electrochromic devices, and to the latest achievements in zinc anode-based electrochromic devices. Additionally, this review delves into the future development trends and perspectives of zinc anode-based electrochromic devices. This review serves as a handbook, which summarizes the history of electrochromism, introduces the physics behind it, highlights the development in zinc anode-based electrochromic devices, and aims to inspire future endeavors into this field, particularly those focused on developing energy-efficient electrochromic devices.