Fatigue‐Resistant Cellulose‐Based Hydrogel Electrolyte for Extended Lifespan of Zinc‐Ion Batteries

Aqueous rechargeable zinc metal batteries (ARZBs) suffer from uncontrolled dendrite growth and parasitic reactions, limiting large-scale deployment. These challenges can be addressed by functional hydrogel electrolytes as alternatives to aqueous ones. Yet their mechanical stability under repeated deformation has been largely overlooked, resulting in poor cycling at long lifetimes or high capacities. Here, we present a sustainable, fatigue-resistant cellulose-based elastomer electrolyte, developed via a two-step network strategy. This design strengthens mechanical properties while introducing negatively charged ion channels that regulate Zn²⁺ desolvation and promote ion transport. Consequently, the electrolyte delivers outstanding mechanical and electrochemical properties, enduring 5000 and 500 compression cycles at 50% and 80% strain, respectively. Achieve 5500 h lifespan at 0.5 mA cm^-2-0.25 mAh cm^-2, and 1000 h even at 28.8 mA cm^-2 with an areal capacity of 28.8 mAh cm^-2, ranking among the best reported. This two-step network strategy establishes a foundation for engineering high-performance hydrogel electrolytes in ARZBs.