Porous Polyacrylamide Electrolytes with Improved Ionic Conductivity for Long-Cycle-Life and High-Power-Density Flexible Zinc–Air Batteries

Abstract Polyacrylamide (PAM) hydrogels are simple to prepare under readily controllable conditions, making them suitable for the large-scale production of high-quality electrolytes. However, when used in zinc–air batteries, continuous water evaporation through the semi-open battery structure causes electrolyte desiccation, reduced ionic conductivity, and increased interfacial contact resistance, ultimately limiting battery performance and cycle life. To address this issue, a porous NaHCO3/PAM hydrogel electrolyte was prepared using a establishes gas-foaming method. NaHCO3 was introduced as an additive and thermally decomposed to generate CO2, producing a highly uniform pore structure. The resulting hydrogel exhibited a more uniform internal pore structure and enhanced electrolyte absorption. Consequently, the resultant flexible zinc–air battery demonstrates a superior peak power density of 163.9 mW cm–2 and an extended cycle life of 81.7 h. This study not only provides establishes a paradigm for designing anti-desiccation hydrogel electrolytes but also paves the way for the development of durable flexible energy storage devices.