Mg-doped layered vanadate for high-energy zinc anode-based electrochromic devices

Abstract

Zinc anode-based electrochromic devices (ZECDs) demonstrate promising prospects in dual-functional electrochromic (EC)-energy storage systems due to their unique optical and energy retrieval properties. Vanadates are widely used in ZECDs due to their diverse color properties, but their cycling stability and kinetics are often hindered by the strong electrostatic interactions between Zn2+ ions and host vanadate lattice. In this study, we fabricated magnesium ions-doped layered vanadates (MVO) with effectively enlarged interlayer spacing, promoting rapid insertion/extraction of Zn2+. Compared to undoped ammonium vanadate (VO), MVO electrode exhibits superior electrochemical capacity (57.6 mAh m-2), faster switching kinetics (tc=79.6 s, tb=25.2 s), enhanced coloration efficiency, and excellent electrochemical reversibility. Finally, the fabricated ZECDs employing MVO films demonstrate exceptional electrochemical reversibility, promising optical switching performance and excellent cycling stability (500 cycles). These results validate the effectiveness of Mg-doping strategy for the modification of layered vanadates for optimized ZECDs coupling EC-energy storage functionalities.