Electronic Regulation Engineering of (NH₄)_0.25WO₃ Anode Enables Fast and Stable Rocking-Chair Zinc-Ion Batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) have emerged as promising candidates for energy storage due to their low cost, high safety, and high theoretical energy density. However, the utilization of Zn anodes results in unsatisfied rate performance and cycling stability due to the Zn dendrites, unsatisfactory stripping/plating efficiency, and gas evolution. Herein, we propose a novel approach to construct "rocking-chair" ZIBs with <i>h</i>-WO₃ as non-Zn anode to address these issues. Metallic and nonmetallic ion-doped <i>h</i>-WO₃ (Cu-NWO) are designed and deliver high capacity as an intercalation anode of "rocking-chair" ZIBs due to their unique delocalized electronic structure and high active sites. Density functional theory calculations certify that the Cu²⁺ preintercalation can strengthen the electrochemical kinetics and simultaneously reduce diffusion barriers on Zn²⁺ storage. The aqueous "rocking-chair" ZIBs deliver a long cycle life and high energy density and successfully realize a self-powered electrochromic device, making them more suitable for practical applications in a smart gird.