Scalable Fabrication of Core–Sheath Nanofiber Yarns via NanoTwist Spinning for High-Performance Energy-Harvesting <i>E</i>-Nanofiber Fabrics

The fabrication of durable and scalable nanofiber fabrics (NFs) remains a critical challenge, limiting their practical applications in wearable electronics, smart textiles, biosensing, and energy harvesting systems. Recent advances in self-powered wearable textiles have demonstrated the potential of converting biomechanical motion into electricity, paving the way for battery-free next-generation SMART textiles. However, achieving a balance among flexibility, durability, high output performance, and wearability remains a major hurdle for real-world adoption. In this study, we introduce NanoTwist Spinning, an integrated nanospinning and yarn-twisting system designed to fabricate core-sheath nanofiber yarns (CSNYs) with high mechanical resilience and electrical conductivity. These yarns feature a precisely twisted nanofiber sheath wrapped around a conductive silver core, enabling large-scale processing through standard knitting machines to produce high-performance electronic-NFs (<i>E</i>-NFs). By optimizing fabrication parameters and utilizing polycaprolactone (PCL) and poly(vinylidene fluoride-<i>co</i>-hexafluoropropylene) (PVDF-HFP) polymers, we achieved uniform, stable CSNYs with an optimized nanofiber wrapping rate of 38.21%. The resulting knitted NFs exhibited exceptional mechanical properties, including 83% compressive resilience, a breaking force of 350.5 N, a tensile strength of 17.53 MPa, and an elongation of 261.8%, ensuring superior durability, wearability, and comfort. To demonstrate real-world feasibility, the fabricated PCL/PVDF-HFP NF-based triboelectric nanogenerator (TENG) achieved an impressive electrical output of 100 V and 8 μA under real-time conditions, validating its potential for energy-harvesting applications. This work marks a significant breakthrough in scalable NYs and NFs production, offering a transformative pathway for the smart textile industry and opening new frontiers in sustainable, self-powered E-Textiles.