Robust Liquid‐Free Supramolecular Ionic Conductive Elastomers Enabled by Hierarchical Hydrogen‐Bond‐Induced Soft Crystalline Strategy for Fiber Electronics

ABSTRACT Fiber electronics that can be miniaturized and seamlessly integrated onto the soft and dynamically deforming human body are emerging as a transformative class of wearable technologies. However, as an indispensable key material, ion conductors face an inherent trade‐off between covalent rigidity and dynamic energy dissipation, making it difficult to achieve spinnability and durability. Herein, a soft crystalline strategy based on dynamic hydrogen‐bond‐induced microcrystalline fracture within polymers is developed to integrate mechanical robustness into stretchable ionic conductors. The molecularly programmed elastomeric matrix contains hierarchical hydrogen bonds spanning a wide energy range, which enable dynamic stretchability through reversible dissociation and reformation, while these hydrogen bonds and the induced microcrystalline fragments synergistically enhance the robustness of ionic conductors. The obtained ionic conductive elastomer exhibits an exceptional combination of stretchability (804.8%), tensile strength (2.2 MPa), and toughness (15.8 MJ m ⁻³ ), together with enhanced solid‐state ionic conductivity enabled by dual‐channel Li ⁺ ion transport. More importantly, the robust liquid‐free ionic conductive elastomer withstands continuous fiber manufacturing and enables the wearable all‐solid‐state electrochromic fibers with long‐term operational stability under high‐curvature deformation and harsh environmental conditions. This work presents a promising paradigm for designing stretchable yet robust ionic conductive elastomers for next‐generation wearable and fiber‐based electronic devices.