Ag2Se-PVDF fabric based flexible thermoelectrics for body heat harvesting

The growing demand for wearable electronics has accelerated the need for sustainable, flexible energy solutions. Thermoelectric fibers offer a promising route by enabling the direct conversion of temperature differences into electrical energy within textile-integrated systems. In this work, we report the fabrication of a flexible thermoelectric fabric by centrifugal spinning of polyvinylidene fluoride (PVDF) fibers, followed by ${\mathrm{Ag}}_2\mathrm{Se}$ coating, cold pressing, and sintering. The resulting ${\mathrm{Ag}}_2\mathrm{Se}$–PVDF fabric exhibits a high Seebeck coefficient of –146 $\mu V/K$ and a power factor of 0.68 $\mathrm{mW}/{\mathrm{mK}}^2$ at room temperature. The fabric maintains excellent flexibility, showing less than 20% resistance degradation after 1400 bending cycles. A prototype thermoelectric textile device constructed from these fibers generates 3.1 $\mu$W at a 40 K temperature gradient and over 0.4 $\mu$W at 10 K. The device consistently produced 13.7 mV under intermittent IR lamp exposure, demonstrating reproducibility and thermal cycling stability. Under a sustained temperature gradient for 59 min, the output voltage remained stable, confirming long-term durability. When applied to the human body, the fabric produced 3.4 mV from just a 5 K temperature difference. This work presents a low-cost and scalable method for producing high-performance inorganic-polymer thermoelectric textiles that offers a viable solution for powering next-generation wearable and e-textile technologies using body heat.