A Knittable Neural‐Inspired MXene‐Aramid Fiber for Wearable High‐Fidelity Signal Transmission

Knittable conductive fibers have emerged as key components for multifunctional textiles used in energy storage, sensing, and protective wear. A persistent challenge in this field, however, is maintaining signal integrity across extended distances within smart textiles. To address this limitation, a core–sheath fiber consisting of a conductive MXene core encapsulated within a mechanically robust aramid nanofiber (ANF) sheath is strategically designed, with each component serving a distinct functional role. We systematically investigate the coagulation process responsible for forming this hierarchical structure and characterize its effect on fiber morphology. The ANF sheath enhances thermal and environmental stability while serving as a protective barrier for the MXene core. This design enables consistent electrical conductivity even after 250 days of air exposure and over 5000 bending cycles. Micro‐computed tomography analysis confirms that the knitted fiber maintains structural integrity and flexibility during hand knitting. Inspired by the myelinated structure of nerve axons, we demonstrate that ANF sheath facilitates efficient signal transmission, enabling woven textiles incorporating these fibers to support long‐distance signal transfer (1.5 m), as shown in the textile‐based touch‐sensing prototype and display applications. These environmentally stable, knittable coaxial fibers exhibit potential for integration into wearable sensors, textile‐based circuits, and wearable human–machine interface devices.