Construction of Alkaline Gel Polymer Electrolytes with a Double Cross-Linked Network for Flexible Zinc–Air Batteries

Flexible zinc-air batteries have broad potential as the next generation of energy storage component in wearable electronic devices. However, the mechanical performance and ionic con-ductivity of electrolytes are urgent issues that hinder the commercial application of flexible batteries. Herein, the alkaline gel polymer electrolyte (AGPE) with a double-network structure is developed, which consists of a covalently cross-linked polyacrylamide (PAM) by in situ polymerization and a physically cross-linked poly(vinyl alcohol) (PVA) by the freeze-thaw method. The freestanding PVA/ N-PAM/KOH gel electrolyte demonstrates high ionic conductivity (309.9 mS cm-1) and excellent mechanical toughness (0.69 MJ m-3), benefiting from the synergistic effect of the double cross-linked system and hydrogen bonds. Meanwhile, the assembled '' sandwich ''-type zinc-air battery presents excellent power density (40.43 mW cm-2), long-term cycle life (113 cycles), super-high-energy efficiency (70.2%), and stable discharge plateau. Impressively, the PVA/N-PAM/KOH-based batteries attached to the human body surface are reliably capable of powering light-emitting diodes.