Fully Elastic Body Heat Powered Wearable Sensing System for Real‐Time Sweat Monitoring at Low Temperatures

ABSTRACT Real‐time biochemical monitoring of rescuers and patients during emergency rescue can significantly improve the rescue efficiency. However, in extreme environments such as disaster sites and plateaus, battery life is adversely affected. This study proposes a fully elastic thermoelectric self‐powered wearable biochemical sensing system, integrating a flexible thermoelectric generator (TEG), fully elastic circuits, and microfluidic chips, aiming to address the challenges of sustainable power supply and stable multi‐parameter monitoring, thereby enabling real‐time multi‐channel monitoring of sodium, potassium, pH, cortisol, and electrocardiogram. To achieve efficient power generation in low‐temperature environments, the system leverages the significant temperature difference between the body surface and the environment. It adopts bismuth telluride thermoelectric legs, serpentine electrodes, and organic filler materials, which together contribute to the development of a flexible TEG device with high power density (17.5 µW/cm 2 ). By combining elastic circuits and microfluidic chips, a fully stretchable (over 30% deformation), low‐temperature resistant (−30°C), and morphologically adaptive integrated platform was constructed. Simulated cold environment validation demonstrated that the system operates stably and can accurately capture the dynamic changes in biomarker concentrations. This fully elastic self‐powered system holds promise for providing reliable and sustained power to flexible wearable devices in emergency environments, significantly enhancing wearability and rescue efficiency.