A highly stretchable thermoelectric generator developed from polyaniline-based nanocomposites for body heat harvesting

Energy harvesting as a result of the temperature difference between the body and environment via the Seebeck effect provides an ideal long-term power supply technique for wearable electronics. Efficient energy utilization requires good thermal contact between a thermoelectric generator (TEG) and human skin, and thus not only good compliance but also high stretchability of a device is necessary. This is still a challenge for TEGs especially without compromising their power generation performance. Here, an approach for realizing highly stretchable TEGs (STEGs) with good TE performance has been developed, where polyaniline-based nanocomposites with p-type tellurium and n-type silver selenide TE nanofillers were employed as TE legs with greatly enhanced TE properties, liquid metal as a stretchable highly conductive interconnect and elastomers for encapsulation. A STEG with only two pairs of p–n legs could generate power of 2.4 mW at a temperature difference of 80 K, together with exhibiting good mechanical robustness and output stability under 80% stretch. The function of a STEG as a body heat harvester is further demonstrated via powering a fan while a wearer is running. Our study provides a promising design and fabrication strategy for STEGs to power wearable electronics.