Full‐Range Strain‐Insensitive Ionic Conduction Enabled by Orthogonal Dynamic‐Bond‐Mediated Microphase Decoupling in Elastomer Fibers

ABSTRACT Stretchable ionic conductors are essential for wearable electronics and iontronic systems. However, their electrical stability is fundamentally limited by strain‐induced resistance changes. Most reported systems exhibit strain‐insensitive behavior only within limited deformation ranges, while maintaining stable ionic conductivity under large strains remains challenging because mechanical deformation simultaneously alters macroscopic conduction pathways and local ion coordination environments. Here, we report a microphase‐engineered ion‐conductive elastomer fiber that spatially decouples mechanical deformation from ionic transport through orthogonal dynamic interactions. This strategy overcomes key fabrication challenges in ion‐conductive fibers, where conventional melt or wet spinning suffers from salt aggregation, thermal degradation, or ion loss. The resulting dual‐continuous architecture selectively integrates hydrogen‐bonded soft domains with lithium‐coordinated rigid conductive domains. The fiber exhibits high stretchability (∼834%), toughness (8.1 MJ m −3 ), and self‐healing efficiency (>80%). Notably, it achieves strain‐insensitive ionic conduction over the full deformation range (0%–834%) with nearly constant resistance (ΔR/R 0 <0.1), outperforming previously reported systems that only work under partial strains. Multiscale characterizations reveal that strain‐induced alignment of rigid conductive domains reduces transport tortuosity while preserving local Li + coordination. The fiber further enables stable signal transmission and reliable operation as a stretchable triboelectric nanogenerator electrode, demonstrating its potential for wearable electronics and iontronic devices.