UV-curable montmorillonite-enhanced gel polymer electrolyte for dendrite-free, enhanced ion transport, and flexible Zn metal batteries

초록

Aqueous Zn-ion batteries (AZBs) are cost-effective and safe, but suffer from narrow electrochemical windows and unstable Zn/electrolyte interfaces. To address these limitations, we designed a gel polymer electrolyte (GPE) incorporating montmorillonite (MMT) as a functional filler. The addition of MMT not only suppresses Zn dendrite growth but also improves Zn2+ ion dissociation and transport, as confirmed by transference number analysis and molecular dynamics simulation. The uniform dispersion of MMT disrupts the polymer crystallinity, increases the amorphous phase and enhances the mechanical flexibility and ionic conductivity. Furthermore, interfacial analyses using scanning electron microscopy and X-ray photoelectron spectroscopy reveal the formation of a stable ZnF2/ZnO-based solid electrolyte interphase, which effectively mitigated dendrite formation. As a result, the GPE-based cell exhibits a significantly improved discharge capacity and long-term cycling stability compared with aqueous liquid electrolyte systems. Pouch cell tests confirm that the capacity is well maintained even under bending, indicating the mechanical flexibility of the system. This study demonstrates that UV-curing, combined with MMT-induced structural tuning is a promising strategy for advancing next-generation Zn-ion batteries applicable to flexible electronics and large-scale energy storage.

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