Rechargeable Aqueous Hybrid Zn2+/Al3+ Electrochromic Batteries

Electrochromic batteries are a newly born technology for next-generation transparent electronics. As electrochromic materials are typically bottlenecked by limited capacity and strict selection of triggered ions, the design of high-performance electrochromic batteries remains an elusive goal. Here, we present an aqueous hybrid Zn2+/Al3+ electrochromic battery system utilizing an electrolyte with both Zn2+ and Al3+. This unique architecture yields remarkable electrochemical performance, including rapid self-coloration time (0.5 s) and switching times (3.9 and 5.1 s for the coloration and bleaching processes), a high optical contrast (88%), and a large areal capacity (185.6 mAh/m2 at 0.5 mA/cm2). Consequently, these properties, which are the highest of any reported electrochromic battery presented to date, mark our hybrid electrolyte architecture as the most promising candidate for future device integration. Furthermore, with the outstanding performance of this safe aqueous electrolyte, our hybrid Zn2+/Al3+ electrochromic battery platform is expected to be a significant catalyst for accelerating the development of electrochromic devices in the future.