Highly Sensitive Thermoelectric Fabric of PEDOT:PSS/SWCNT@PU Composite Fibers for Body‐Temperature Monitoring and Fever Alarming

Abstract Integrated flexible thermoelectric (TE) fabric demonstrates great potential for wearable energy harvesting and intelligent temperature sensing. However, existing TE fibers often struggle to simultaneously satisfy requirements for high and stable TE performance, favorable weavability, sweat resistance, and good biocompatibility. Herein, continuous PEDOT:PSS/SWCNT composite fibers with these desirable features are obtained via a convenient freeze‐thaw‐induced gelation process assisted wet‐spinning process, exhibiting a high electrical conductivity of 1960 S cm −1 , a large power factor of 59.6 µW m −1 K −2 , and a high tensile strength of 103 MPa. Polyurethane‐encapsulated composite fibers further provide superior mechanical flexibility, desirable weavability, remarkable washability, low‐temperature tolerance, and stable TE performance over 1000 bending/twisting cycles. A resulting TE fabric comprising 32 p‐type legs achieves a power density of 60.1 µW cm −2 at temperature difference of 50 K, surpassing most reported PEDOT:PSS‐based fiber devices, and retains over 95% performance after various mechanical deformations. The developed fabric‐integrated intelligent fever monitoring system (forehead/wrist/armpit) exhibits high sensitivity (alarm response < 5 s) and good repeatability (3–4.3 s response over 50 cycles) for low/high fever monitoring. Such composite TE fibers are anticipated to advance practical applications of wearable TE fabrics in body energy harvesting, personalized healthcare, and intelligent fitness monitoring.