Solid-State Rechargeable Zinc-Air Battery with Long Shelf Life Based on Nanoengineered Polymer Electrolyte

Zinc-air batteries (ZABs) are vulnerable to the ambient environment (e.g., humidity and CO₂ ), and have serious selfdischarge issues, resulting in a short shelf life. To overcome these challenges, a near-neutral quaternary ammonium (QA) functionalized polyvinyl alcohol electrolyte membrane (different from conventional alkali-type membranes) has been developed. QA functionalization leads to the formation of interconnected nanochannels by creating hydrophilic/-phobic separations at the nanoscale. These nanochannels selectively transport OH^- ions with a reduced migration barrier, while inhibiting [Zn(NH₃ )₆ ]²⁺ crossover. Owing to the superior water retention ability and enhanced chemical stability of the membrane, the solid-state zinc-air battery (SZAB) displays outstanding flexibility, a promising cycle lifetime, and a large volumetric energy density. More importantly, the self-discharge rate of SZAB is depressed to less than 7 % per month, and the fully dehydrated SZAB could recover its rechargeability upon replenishment of the solution of NH₄ Cl.