High-Performance Fatigue-Resistant Dual- Polyrotaxane Hydrogel Electrolytes for Flexible Aqueous Zinc-Ion Batteries

This study presents a novel anti-fatigue hydrogel electrolyte with a slip-ring structure for next-generation flexible wearable energy storage systems. Conventional quasi-solid aqueous zinc-ion batteries (ZIBs) with hydrogel electrolytes often suffer from mechanical degradation under repeated stress, limiting practical use. To overcome this, a dual-Polyrotaxane (DPR)-polyacrylic acid (PAA) hydrogel with a unique slip-ring architecture is synthesized, that enhances mechanical durability, self-healing, and adhesion. The interwoven DPR and PAA networks distribute stress evenly, ensuring high ionic conductivity while preventing zinc dendrites and parasitic reactions for uniform zinc deposition during cycling.When applied to a flexible quasi-solid-state Zn-MnO₂ battery, this hydrogel achieves a specific capacity of 295 mAh g⁻¹ MnO₂ at 0.5C, retains 147 mAh g⁻¹ at 5C, and shows 81.52% capacity retention after 1000 cycles. The battery also demonstrates exceptional stability, with zinc pairs lasting over 1750 h at 5 mA cm⁻². Furthermore, it maintains reliable operation under mechanical stresses like pressing, folding, and twisting, making it ideal for wearable applications. This work advances hydrogel electrolyte design, offering a durable, high-performance solution for flexible energy storage systems.