Dual-Crosslinked PVA-Based Hydrogel Electrolyte with High Toughness Prepared by Electron Beam Irradiation for Aqueous Zn-Ion Supercapacitors

Aqueous zinc-ion supercapacitors are regarded as promising energy storage devices due to their high safety, low cost and environmental friendliness. However, conventional preparation methods for dual-crosslinked hydrogel electrolytes typically require initiators or chemical crosslinking agents and involve complex processing procedures. These requirements not only increase production cost but may also introduce environmental concerns. To overcome these limitations, this study builds upon a novel electron beam (EB) irradiation strategy developed in our previous research and further extends its advantages. The core innovation of this study is the introduction of glycerol (G), which converts the EB irradiation–induced crosslinking mechanism from a predominantly physical network, as observed in single-component polyvinyl alcohol (PVA) hydrogels, into a synergistic covalent/physical dual network. This fundamental shift in network architecture underpins the observed performance enhancements. Herein, we report a dual-crosslinked PVA–G hydrogel electrolyte fabricated via EB irradiation without any chemical crosslinking agents or initiators. The results demonstrate that an optimal irradiation dose of 30 kGy yields a PVA–G hydrogel with excellent overall performance, including a maximum tensile strength of 71 kPa and an elongation at break of 104.61%. Notably, compared with our previous study (in which PVA hydrogel at 30 kGy exhibited a maximum tensile strength of 78 kPa and an elongation at break of approximately 7.63%), the elongation at break of the PVA–G dual-crosslinked hydrogel is drastically increased, confirming its substantially improved mechanical properties. Furthermore, the hydrogel exhibits a high ionic conductivity of 22.8 mS cm -1 and an expanded electrochemical stability window of approximately 2.51 V. This study presents a cost-effective, simple and scalable strategy for producing high-performance dual-crosslinked hydrogel electrolytes and further demonstrates the versatility and superiority of EB irradiation technology for advancing aqueous energy storage materials.