High figure-of-merit and power generation in high-entropy GeTe-based thermoelectrics
High figure-of-merit and power generation in high-entropy GeTe-based thermoelectrics
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高熵 GeTe 基热电器件的高品质因数和发电
DOI：
10.1126/science.abq5815
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发表时间：
2022-07-08
期刊：
影响因子：
56.9
通讯作者：
He, Jiaqing
中科院分区：
文献类型：
--
作者：
Jiang, Binbin;Wang, Wu;He, Jiaqing
高熵概念提供了扩展的、优化的组合物空间，从而产生不寻常的输运现象和优异的热电性能。通过调整电子和声子的定位，我们将碲化锗基高熵材料在750开尔文时的品质值提高到2.7，并在506开尔文的温差下实现了13.3%的实验转换效率。通过增加熵，晶体对称性的增加使电子在扭曲的菱形结构中的分布离域，从而导致能带收敛和电学性能的改善。相比之下，来自熵诱导无序的局域声子抑制了横向声子的传播，这是导致非调和性增加和晶格热导率大大降低的原因。我们提供了一个通过熵操纵来调整电子和声子定位的范例，但我们也展示了提高高熵热电材料性能的途径。
The high-entropy concept provides extended, optimized space of a composition, resulting in unusual transport phenomena and excellent thermoelectric performance. By tuning electron and phonon localization, we enhanced the figure-of-merit value to 2.7 at 750 kelvin in germanium telluride-based high-entropy materials and realized a high experimental conversion efficiency of 13.3% at a temperature difference of 506 kelvin with the fabricated segmented module. By increasing the entropy, the increased crystal symmetry delocalized the distribution of electrons in the distorted rhombohedral structure, resulting in band convergence and improved electrical properties. By contrast, the localized phonons from the entropy-induced disorder dampened the propagation of transverse phonons, which was the origin of the increased anharmonicity and largely depressed lattice thermal conductivity. We provide a paradigm for tuning electron and phonon localization by entropy manipulation, but we have also demonstrated a route for improving the performance of high-entropy thermoelectric materials.