Improved Energy Harvesting Efficiency in Thermoelectric Generators Enabled by Combining Segmented Materials with Asymmetric Leg Configurations

Thermoelectric generators (TEGs) that can convert waste heat into useable electricity are recognized as a significant tool in the quest for clean energy generation. Achieving higher thermoelectric (TE) energy conversion output of TEG is a fundamental challenge that can be realized through testing a combinatorial approach of materials, shapes of legs, and device designs. Herein, we demonstrated the segmented trapezoidal-shaped leg (STSL)-based TEG by combining the segmented Bi0.5Sb1.5Te3 and Sn0.85Sb0.15Te1 TE materials with asymmetric leg configurations; subsequently, TE output performance of fabricated STSL-based TEGs was compared with TEGs based on the individual cubical-shaped leg (CSL) and the segmented cubical-shaped leg (SCSL). A STSL-TEG generates a remarkable output power of 345 μW at input heat of 773 K, compared to the SCSL-TEG (131 μW) and CSL-TEGs (63 μW for Bi0.5Sb1.5Te3 and 46 μW for Sn0.85Sb0.15Te1). Electron probe microanalysis explicitly reveals the interdiffusion layer between Bi0.5Sb1.5Te3 and Sn0.85Sb0.15Te1, demonstrating a complex interplay of elemental interactions and a gradual transition of various elements (Bi, Te, Sn, and Sb) at the interface. Furthermore, to support the synergistic effect of controlling geometry and design of TE legs in TEGs, the performance of segmented TEGs and asymmetrical leg designs were systematically evaluated by the multiphysics simulations based on finite element analysis. The proposed study demonstrates the potential of combining segmented materials with asymmetric leg geometries, such as shape and size, to significantly improve the efficiency and output power of TEGs, paving the way for developing high-performance clean energy harvesting devices and their applications.