Gel polymer electrolytes based on compound cationic additives for environmentally adaptive flexible zinc-air batteries with a stable electrolyte/zinc anode interface

Abstract

With the rapid development of flexible wearable technology, there is an urgent need for the exploitation of flexible and sustainable energy storage devices. Flexible zinc-air battery (ZABs) have attracted extensive attention from researchers due to their high theoretical energy density, abundant raw material and environmental friendliness. However, there is no more effective strategy to solve the problems of dendrite growth and by-products formation on the zinc anode surface of flexible ZABs in a strong alkaline environment. Herein, the PMA-HLx hydrogels based on chitosan quaternary ammonium salt (HACC) and La³⁺ as compound cationic additives are prepared as gel polymer electrolytes (GPEs) for flexible ZABs. The optimal PMA-HL0.02 GPE shows admirable interfacial adhesion and favorable ionic conductivity of 130.43 mS cm⁻¹. Meanwhile, the assembled flexible ZAB exhibits excellent electrochemical performance and long cycle life, as well as a stable charge-discharge voltage gap at different bending angles, and still has favorable power densities of 113.2 mW cm⁻² and 93.65 mW cm⁻² at -20°C and 80°C, respectively. Therefore, this synthesis strategy of GPEs based on compound cationic additives provides a useful reference for the development of flexible ZABs with environmental adaptability and interfacial stability in alkaline electrolyte environment.