All‐Fiber‐Type Temperature Sensor Powered by Zinc‐Ion Battery toward Wearable Sensing Clothes for Health Monitoring

Abstract Continuous and accurate monitoring of body temperature is vital for human healthcare. However, existing flexible temperature sensors face challenges such as poor reproducibility owing to thermal influences and reliance on bulky external power supplies, which limit wearability. To address these issues, a highly reproducible and self‐powered fiber‐based temperature sensor is developed. The fiber‐type sensor employs an optimized aramid/polyvinyl alcohol (PVA) substrate with a near‐zero thermal expansion coefficient combined with a highly conductive dual‐filler network of reduced graphene oxide (rGO) and manganese dioxide (MnO ₂ ), suppressing temperature‐induced signal drift. The sensor demonstrates higher stability and repeatability, shows a linear response in the temperature range of 20−55 °C, and features a fast response of 120 ms and superresolution (0.1 °C). For the fiber‐type battery, a MnO ₂ ‐decorated carbon fiber cathode and a zinc wire anode are bonded by a gel polymer electrolyte encapsulated in Ecoflex, delivering a high open‐circuit voltage (1.49 V) and large capacity (278 mAh g ⁻¹ ). The practicality of the system is demonstrated by embedding a fiber sensor and battery into clothing, enabling continuous body temperature monitoring and early fever detection through subtle abnormal temperature variations.