Intensive suppression of thermal conductivity in Nd0.6Fe2Co2Sb12-xGex through spontaneous precipitates
Intensive suppression of thermal conductivity in Nd0.6Fe2Co2Sb12-xGex through spontaneous precipitates
复制标题
DOI：
10.1063/1.4819889
复制
发表时间：
2013-08
影响因子：
3.2
通讯作者：
Long Zhang;F. Duan;Xiaodong Li;Xinlin Yan;Wentao Hu;Li-Min Wang;Zhongyuan Liu;Yongjun Tian;
中科院分区：
文献类型：
--
作者：
Long Zhang;F. Duan;Xiaodong Li;Xinlin Yan;Wentao Hu;Li-Min Wang;Zhongyuan Liu;Yongjun Tian;
最佳的p型方晶均为富铁方晶，其热膨胀系数大于基于cosb3的n型方晶，这降低了p型和n型方晶构成的热电偶的可靠性。在本研究中，我们用等量的Fe和Co合成了Nd0.6Fe2Co2Sb12-xGex（0≤x≤1）。微观结构分析揭示了沉淀相的独特微观结构，包括角方石基体中的纳米沉淀物，结构不完善的纳米颗粒（小于100 nm），以及前所未有的厚度约10 nm的薄层覆盖。这种丰富的微结构控制了声子的全长尺度散射，显著抑制了晶格热导率。结果表明，与无Ge样品相比，Nd0.6Fe2Co2Sb11.7Ge0.3的ZT提高了50%，即使功率因数略有降低。
The best p-type skutterudites are all Fe-rich and show larger coefficient of thermal expansion than CoSb3-based n-type skutterudites, which deteriorate the reliability of thermoelectric couples constituted by p- and n-skutterudites. In this study, we synthesize Nd0.6Fe2Co2Sb12-xGex (0≤x≤1) with equal amounts of Fe and Co. Microstructure analysis reveals a unique microstructure of precipitate phases, including nanoprecipitates in skutterudite matrix, structurally imperfect nanoparticles (less than 100 nm), and unprecedented thin-layer coverings about 10 nm thick. Such rich microstructures dominate the scattering of phonons with full-length scale and remarkably suppress the lattice thermal conductivity. As a result, ZT for Nd0.6Fe2Co2Sb11.7Ge0.3 is 50% improved compared with that of a Ge free sample even with a moderately decreased power factor.