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Highlights: La3+/Na+ bimetallically doped vanadate, designed for the first time, is promising in many electrochemical applications (e.g., batteries, electrochromics). This is the first report of electrochromic displays employing bimetallically doped vanadate. It is demonstrated for the first time that zinc dendrites and vanadate dissolution are significantly inhibited by employing an aqueous hybrid Zn2+/Na+ electrolyte. Vanadates are a class of the most promising electrochromic materials for displays as their multicolor characteristics. However, the slow switching times and vanadate dissolution issues of recently reported vanadates significantly hinder their diverse practical applications. Herein, novel strategies are developed to design electrochemically stable vanadates having rapid switching times. We show that the interlayer spacing is greatly broadened by introducing sodium and lanthanum ions into V3O8 interlayers, which facilitates the transportation of cations and enhances the electrochemical kinetics. In addition, a hybrid Zn2+/Na+ electrolyte is designed to inhibit vanadate dissolution while significantly accelerating electrochemical kinetics. As a result, our electrochromic displays yield the most rapid switching times in comparison with any reported Zn-vanadate electrochromic displays. It is envisioned that stable vanadate-based electrochromic displays having video speed switching are appearing on the near horizon. [ABSTRACT FROM AUTHOR]

The development of electrochromic materials has opened the door to the development of numerous devices including smart windows, color displays, optical filters, wearable camouflages, among others. Although the current electrochromic devices do not consume energy while maintaining their colored or colorless states, their bistable operation requires external electrical energy to be consumed during switching. To reduce the energy consumption of an electrochromic device, an emerging Zn anode‐based electrochromic device concept was recently introduced to partially retrieve the consumed electrical energy. In this Review, key technological developments and scientific challenges are presented for a broad range of Zn anode‐based electrochromic device configurations with emphasis on the inherent distinctions between the Zn anode‐based and conventional electrochromic devices. Specifically, a comprehensive comparison of the two classes of electrochromic devices in the high‐performance device design is provided. For the electrochromic layer, the methods for obtaining high‐quality electrochromic materials and thin films are reviewed. For the electrolytes, the effect of the dual ion system on the electrochromic performance is discussed. Also, some critical but unresolved issues in the device design and fabrication are discussed. The perspectives and outlook at the end of this Review provide recommendations to improve performance for future electrochromic studies. [ABSTRACT FROM AUTHOR]