Soft\nand Stretchable Thermoelectric Generators Enabled\nby Liquid Metal Elastomer Composites

Abstract

Stretchable\nthermoelectric generators (TEGs) capable of harvesting\nelectrical energy from body heat under cold weather conditions have\nthe potential to make wearable electronic and robotic systems more\nlightweight and portable by reducing their dependency on on-board\nbatteries. However, progress depends on the integration of soft conductive\nmaterials for robust electrical wiring and thermal management. The\nuse of thermally conductive soft elastomers is especially important\nfor conforming to the body, absorbing body heat, and maintaining a\ntemperature gradient between the two sides of the TEGs in order to\ngenerate power. Here, we introduce a soft-matter TEG architecture\ncomposed of electrically and thermally conductive liquid metal embedded\nelastomer (LMEE) composites with integrated arrays of n-type and p-type\nBi₂Te₃ semiconductors. The incorporation of\na LMEE as a multifunctional encapsulating material allows for the\nseamless integration of 100 thermoelectric semiconductor elements\ninto a simplified material layup that has a dimension of 41.0 ×\n47.3 × 3.0 mm. These stretchable thermoelectric devices generate\nvoltages of 59.96 mV at Δ10 °C, 130 mV at Δ30 °C,\nand 278.6 mV and a power of 86.6 μW/cm² at Δ60\n°C. Moreover, they do not electrically or mechanically fail when\nstretched to strains above 50%, making them well-suited for energy\nharvesting in soft electronics and wearable computing applications.