Starch-Based Superabsorbent Hydrogel with High Electrolyte Retention Capability and Synergistic Interface Engineering for Long-Lifespan Flexible Zinc-Air Batteries

The advent of wearable electronics has strongly stimulated advanced research into the exploration of flexible zinc-air batteries (ZABs) with high theoretical energy density, high inherent safety, and low cost. However, the half-open battery structure and the high concentration of alkaline aqueous environment pose great challenges on the electrolyte retention capability and the zinc anode stability. Herein, a starch-based superabsorbent hydrogel polymer electrolyte (SSHPE) with high ionic conductivity, electrolyte absorption and retention capabilities, strong alkaline resistance and high zinc anode stability has been designed and applied in ZABs. Experimental and calculational analyses probe into the root of the superiority of SSHPEs, confirming the significance of the carboxyl functional groups along their polymer chains. These features endow the as-fabricated ZAB a long cycle life of 300 h, much longer than that with commonly used poly(vinyl alcohol)-based electrolyte.

Automated summary

The development of wearable electronics has driven the research on flexible zinc-air batteries (ZABs) with high energy density, safety, and low cost. However, the unique battery structure and the alkaline environment present challenges to the electrolyte retention and zinc anode stability. In this study, a starch-based superabsorbent hydrogel polymer electrolyte (SSHPE) was developed to address these challenges, and it showed superior performance compared to commonly used poly(vinyl alcohol)-based electrolyte.