Dual Action of Zeolite and Polyethylene Glycol Enables Robust and Ion-Conductive Poly(vinyl alcohol)-Based Hydrogel Electrolytes for Stable Zinc-Ion Batteries

Abstract Zinc-ion batteries (ZIBs) are promising candidates for large-scale energy storage owing to their high theoretical capacity, low cost, environmental benignity, and intrinsic safety. However, their practical application remains limited by interfacial side reactions at the Zn anode and insufficient electrolyte stability. Herein, a zeolite/PEG comodified PVA hydrogel electrolyte was developed by incorporating LTA zeolite and polyethylene glycol (PEG) into a poly(vinyl alcohol) (PVA) matrix. LTA zeolite enhances water retention, regulates Zn2+ transport, and improves electrolyte stability by confining free water, whereas hydrogen-bonded network between PEG and PVA improves mechanical flexibility and provides more continuous ion-conduction pathways. Owing to the dual effects of PEG and zeolite, PZ-10 retained water for 48 h and exhibited an elongation at break of 420%, while PP5-Z-10 maintained flexibility after 72 h and achieved an ionic conductivity of 1.72 × 10−2 S cm−1, 5.2 times that of pristine PVA. When assembled into ZIBs, the PP5-Z-10 electrolyte delivered a specific capacity of 190.1 mAh g−1 at 50 mA g−1 and retained 86.7% of its capacity after 500 cycles at 1000 mA g−1. These results demonstrate that the dual action of PEG and zeolite effectively improves the durability, ionic conductivity, and cycling stability of PVA-based hydrogel electrolytes, providing a practical strategy for stable Zn-based energy storage devices.