Half-Heusler compounds exhibit significant potential in thermoelectric applications for power generation up to 1000 K, notwithstanding the substantial challenges posed by the cost of constituent elements and the imperative to augment the average thermoelectric figure-of-merit (zT_ave) for more practical applications. Overcoming these obstacles demands advancing high-performance p-type TaFeSb thermoelectric materials with diminished Ta content. This investigation systematically explores the quaternary-phase space encompassing Ta, Nb, V, and Ti to ascertain an optimal composition, namely Ta_0.42Nb_0.3V_0.15Ti_0.13FeSb. This composition is characterized by a remarkable reduction in Ta concentration and an enhancement in zT, peaking at 1.23 at 973 K. Moreover, the integration of a high-mobility secondary phase, InSb, fosters enhancements in both the Seebeck coefficient and electrical conductivity, resulting in a 23% augmentation in the average power factor in the optimized composite, Ta_0.42Nb_0.3V_0.15Ti_0.13FeSb-(InSb)_0.015. This optimized material achieves a peak zT of 1.43 at 973 K, and a record-setting zT_ave of 1 from 300 K to 973 K, marking a significant advancement among p-type half-Heusler materials. Additionally, a single-leg device demonstrates a peak efficiency of approximately 8% under a temperature difference of 823 K vs. 303 K. These findings underscore the substantial potential of the proposed material design and fabrication methodologies in fostering efficient and sustainable thermoelectric applications.

中文翻译：

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通过成分和复合材料优化实现 P 型 TaFeSb 基热电材料的性能进步


Half-Heusler 化合物在高达 1000 K 的热电发电应用中表现出巨大的潜力，尽管组成元件的成本带来了巨大挑战，并且必须提高平均热电品质因数 （zT_ave） 才能用于更实际的应用。克服这些障碍需要发展 Ta 含量降低的高性能 p 型 TaFeSb 热电材料。本研究系统地探索了包含 Ta、Nb、V 和 Ti 的四元相空间，以确定最佳组成，即 Ta_0.42Nb_0.3V_0.15Ti_0.13FeSb。这种成分的特点是 Ta 浓度显着降低和 zT 增强，在 973 K 处达到 1.23 的峰值。此外，高迁移率二次相 InSb 的集成促进了塞贝克系数和电导率的增强，从而使优化复合材料的平均功率因数提高了 23%，Ta_0.42Nb_{0.3 V 0.15}Ti_0.13FeSb-（InSb）_0.015。这种优化的材料在 973 K 时实现了 1.43 的峰值 zT，在 300 K 至 973 K 时实现了创纪录的 1 zT_ave，这标志着 p 型半 Heusler 材料的重大进步。此外，在 823 K 和 303 K 的温差下，单臂器件的峰值效率约为 8%。 这些发现强调了拟议的材料设计和制造方法在促进高效和可持续的热电应用方面的巨大潜力。