Strategies for Developing Intrinsically Stretchable Thermoelectric Materials

Thermoelectric (TE) energy harvesting can directly convert thermal energy into electrical energy, offering a promising solution to utilize the waste heat generated in the industry and energy consumption cycles. Such TE materials offer distinct advantages such as solid-state energy conversion without any vibration and by-products and thus have a potential as sustainable energy harvesting platforms. Conventional TE research efforts have focused primarily on improving the figure of merit to enhance energy conversion efficiency. Nevertheless, as the shape of the heat sources is diversifying and mechanically deforming targets continue to emerge, there is a growing demand for intrinsically stretchable TE materials. Most of the conventional TE materials lack sufficient stretchability which can ensure sustainable thermal energy harvesting in mechanically dynamic and harsh environment. This review provides an overview of recent progress in the development of intrinsically stretchable TE materials, including stretchable conductive polymer composites, ductile inorganic semiconductors, and novel deformable materials. We further evaluate the resulting TE performance of each strategy and its stability under mechanical deformation, finally broadening our scope to applications of the developed stretchable TE materials into practical use.