Thermoelectric materials convert heat flux to electricity (or vice versa as Peltier coolers); however, their application to harvest waste heat is limited by challenges in fabrication and materials optimization. Here, cold-spray deposition is used as an additive manufacturing technique to fabricate p- and n-type Bi2Te3, on substrates ranging from quartz to aluminum. The sprayed material has a randomly oriented microstructure largely free from pores (> 99.5% dense), and deposition is achieved without substantial compositional changes. The Seebeck coefficient and thermal conductivity are largely preserved through the spray process, but the defects introduced during deposition significantly increase electrical resistivity. Defects can be removed, and compressive strain relaxed by a post-deposition anneal, which leads to Bi2Te3 blocks with a typical ZT of 0.3 at 100°C. Generators fabricated on sheets or pipes made of copper compare favorably with similar designs constructed using bulk Bi2Te3, displaying a wider operating temperature range. These results demonstrate the power and versatility of cold-spray additive manufacturing and provide a pathway toward fabrication of thermoelectric generators in complex geometries that are inaccessible to generators made by traditional approaches.

中文翻译：

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热电材料的冷喷涂沉积

热电材料将热通量转化为电能（反之亦然，如珀尔帖冷却器）；然而，它们在收集废热方面的应用受到制造和材料优化方面的挑战的限制。在这里，冷喷涂沉积用作增材制造技术，在从石英到铝的基板上制造 p 型和 n 型 Bi2Te3。喷涂材料具有随机取向的微观结构，基本上没有孔隙（> 99.5% 致密），并且在没有实质性成分变化的情况下实现沉积。塞贝克系数和热导率在很大程度上通过喷涂工艺得以保留，但沉积过程中引入的缺陷会显着增加电阻率。可以去除缺陷，并通过沉积后退火来放松压缩应变，这导致 Bi2Te3 块在 100°C 下具有 0.3 的典型 ZT。在由铜制成的板材或管道上制造的发电机与使用大块 Bi2Te3 构建的类似设计相比具有优势，显示出更宽的工作温度范围。这些结果证明了冷喷涂增材制造的强大功能和多功能性，并为制造复杂几何形状的热电发电机提供了一条途径，而传统方法制造的发电机无法做到这一点。