Weavable thermoelectric fibers with hierarchically porous architecture-mediated ion transport

Harvesting low-grade thermal energy via wearable electronics necessitates materials that integrate high thermoelectric performance with excellent flexibility and wearability. Although ionic thermoelectric (iTE) materials intrinsically exhibit giant Seebeck coefficients (Sᵢ), their practical implementation remains largely constrained by their conventional film or bulk architectures. Herein, we report a high-performance, weavable iTE fiber fabricated through a scalable strategy combining wet spinning with ionic liquid (IL) impregnation. By precisely tuning the coagulation bath, a hierarchically porous architecture is engineered within the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix. This unique structural design is proposed to mediate ion transport, establishing a strong structure-dependent correlation that endows the resulting fiber with an outstanding ionic Sᵢ of -8.23 mV K^-1, exceptional thermal stability, and adequate mechanical toughness for wearable applications. Furthermore, the fiber demonstrates a remarkably broad strain-sensing range (0-166.21%) with stable and highly reproducible electrical responses to stretching, compression, and bending, enabling its multi-functional application as a self-powered sensor. This work provides a facile and efficient strategy for developing fiber-shaped iTE materials, paving the way for their integration into smart textiles for dual-mode energy harvesting and biomechanical sensing.