Printing Liquid Metal Elastomer Composites for High-Performance Stretchable Thermoelectric Generators

摘要

Continuous powering of wearable electronics and personalized biomonitoringsystems remains a great challenge. One promising solution is the use ofthermoelectric generators (TEGs) that convert body heat to electricity. Theseenergy harvesters must conform to curved surfaces and minimize thermalbarriers to maintain efficiency while still exhibiting durability under largedeformations. Here, highly efficient, stretchable thermoelectric generatorsmade of inorganic semiconductors and printed multifunctional soft matterare introduced. Liquid metal elastomer composites with tailored microstructuresare printed as highly conductive thermal interface materials andstretchable interconnects. Additionally, elastomer composites with hollowmicrospheres are formulated to print a deformable and lightweight thermalinsulator within the device. These stretchable thermoelectric wearables showan excellent performance by generating an open-circuit voltage of 392 mVand a power density of ≈650 μW cm~(?2) at ΔT = 60 ℃ and withstandingmore than 15 000 stretching cycles at 30 strain. Furthermore, the additivemanufacturing process is leveraged by direct writing of the TEGs on textilesto demonstrate their seamless integration and by 3D printing of stretchableheatsinks to maintain a large temperature gradient across the device and tostudy the effect of convective heat transfer on device performance.