Waste Fabric‐Derived Aerogel Fiber for Self‐Powered Tactile Sensing with High Sensitivity

Abstract The nanofluidic fibers with unique ion‐selective transport enable the osmotic power generation and self‐powered sensing. However, the extremely nanoconfined channels in these fibers result in high internal resistance, limiting energy harvesting and the detection sensitivity of fiber‐based sensors. In this work, aramid nanofibers (ANFs)‐based aerogel fibers fabricated using waste fabrics are exploited as an ion transporter for energy conversion and self‐powered sensors. Benefiting from the 3D nanoporous structure, the aerogel fiber exhibits an internal resistance of ca. 10 kΩ under 500‐fold NaCl, much less than that of traditional energy generators (e.g., several tens of thousands of ohms). The low internal resistance results in enhanced output power density (17.6 W m −2 ) under 500‐fold NaCl gradient. Moreover, the ANFs aerogel fibers remain stable in solutions over 30 days in terms of structure integrity and power generation capacity. Notably, the aerogel fibers demonstrate an ultra‐fast response with a response time of 25 ms and an ultra‐low detection limit of 0.20 mN, enabling real‐time sensing of motions and movements. These features highlight their substantial potential as self‐powered sensors with ultra‐high sensitivity, significantly advancing the development of fiber‐based sensors.