Long-Shelf-Life Polymer Electrolyte Based on Tetraethylammonium Hydroxide for Flexible Zinc–Air Batteries

Flexible zinc-air batteries (ZABs) have been considered as one of the most outstanding energy storage devices for flexible and portable electronics because of their superior energy density and environmental friendliness. As the "blood" of flexible ZABs, electrolytes play a significant role in determining their performance, such as discharge working time, cycling property, and shelf life. Herein, a novel polymer electrolyte based on quaternary ammonium hydroxides is first applied in flexible zinc-air batteries. Tetraethylammonium hydroxide (TEAOH) is innovatively used as the ionic conductor with poly(vinyl alcohol) (PVA) as the polymer host in the polymer electrolyte and exhibits a good water retention capability, resulting in not only a good shelf life but also a good working life of the flexible zinc-air batteries. The fabricated polymer electrolyte maintains its high ionic conductivity of 30 mS cm-1 even after 2 weeks. In addition, the as-assembled zinc-air batteries based on the TEAOH-PVA electrolyte exhibit excellent discharge performance and cycling life compared to those based on the commonly used KOH-PVA electrolyte, and no notable degradation is observed after 2 weeks. Furthermore, flexible TEAOH-PVA-based zinc-air batteries can power a light-emitting diode (LED) electronic watch, a mobile phone, and an LED screen, indicating the very large potential of the high-performance zinc-air batteries that are safe, cost-effective, and remarkably flexible.