Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus, Denmark.
TEGnology ApS, Lundagervej 102, DK-8722 Hedensted, Denmark.
Nat Commun. 2017 Jan 6;8:13901. doi: 10.1038/ncomms13901.
Widespread application of thermoelectric devices for waste heat recovery requires low-cost high-performance materials. The currently available n-type thermoelectric materials are limited either by their low efficiencies or by being based on expensive, scarce or toxic elements. Here we report a low-cost n-type material, Te-doped MgSbBi, that exhibits a very high figure of merit zT ranging from 0.56 to 1.65 at 300-725 K. Using combined theoretical prediction and experimental validation, we show that the high thermoelectric performance originates from the significantly enhanced power factor because of the multi-valley band behaviour dominated by a unique near-edge conduction band with a sixfold valley degeneracy. This makes Te-doped MgSbBi a promising candidate for the low- and intermediate-temperature thermoelectric applications.
广泛应用于余热回收的热电设备需要低成本、高性能的材料。目前可用的 n 型热电材料要么效率低，要么基于昂贵、稀缺或有毒元素。在这里，我们报告了一种低成本的 n 型材料，即掺 Te 的 MgSbBi，它在 300-725 K 范围内表现出非常高的品质因数 zT，范围从 0.56 到 1.65。通过结合理论预测和实验验证，我们表明，由于独特的近边缘导带具有六重谷简并，多谷能带行为导致的功率因子显著增强是其具有高热电性能的原因。这使得掺 Te 的 MgSbBi 成为低温和中温热电应用的有前途的候选材料。
