Anisotropy and inhomogeneity are ubiquitous in spark plasma sintered thermoelectric devices. However, the origin of inhomogeneity in thermoelectric nanocomposites has rarely been investigated so far. Herein, we systematically study the impact of inhomogeneity in spark plasma sintered bismuth antimony telluride (BiSbTe) thermoelectric nanocomposites fabricated from solution-synthesized nanoplates. The figure of merit can reach 1.18, which, however, can be overestimated to 1.88 without considering the inhomogeneity. Our study reveals that the inhomogeneity in thermoelectric properties is attributed to the non-uniformity of porosity, textures and elemental distribution from electron backscatter diffraction and energy-dispersive spectroscopy characterizations. This finding suggests that the optimization of bulk material homogeneity should also be actively pursued in any future thermoelectric material research.

中文翻译：

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火花等离子体烧结碲化铋锑热电纳米复合材料的不均匀性成因

各向异性和不均匀性在火花等离子体烧结热电装置中普遍存在。然而，迄今为止，很少研究热电纳米复合材料中的不均匀性。在本文中，我们系统地研究了不均匀性对由溶液合成纳米板制备的火花等离子体烧结碲化铋锑（BiSbTe）热电纳米复合材料的影响。品质因数可以达到1.18，但是在不考虑不均匀性的情况下可以被高估为1.88。我们的研究表明，热电性能的不均匀性归因于孔隙率，织构和元素分布的不均匀性，这些不均匀性来自电子背散射衍射和能量色散光谱表征。