Regulating the gradient water distribution via hydro-philic/phobic compositional design in ionogels for stable zinc ion batteries

Abstract

Zinc-ion batteries (ZIBs) are promising candidates for next-generation energy storage systems due to their safety, cost-effectiveness, and environmental friendliness. However, the trade-offs between hydrogel and ionogel electrolytes, such as restricted electrochemical windows in hydrogels and sluggish ion migration in ionogels, pose significant challenges to achieving stable and efficient ZIB performance. In this study, an innovative ionogel electrolyte with a gradient water distribution (GW-IGE) was developed by modulating the hydrophilic and hydrophobic composition. This design optimally balances hydration levels to enhance ionic transport and suppress dendrite formation. The resulting GW-IGE achieves a high ionic conductivity of 5.04 mS cm⁻¹, an extended electrochemical cycling life of over 7000 h, and an average Coulombic efficiency of 99.4 %. Furthermore, the Zn||PANI full cell demonstrates excellent capacity retention of 90 %. This work highlights the effectiveness of gradient water regulation in ionogel electrolytes, providing a new pathway for the advancement of high-performance ZIBs.