Li Xu-Guang, Liu Wei-Di, Li Shuang-Ming, Li Dou, Zhong Hong, Chen Zhi-Gang
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
Centre for Future Materials, University of Southern Queensland, Springfield Central, Queensland 4300, Australia.
ACS Appl Mater Interfaces. 2021 Nov 17;13(45):54185-54193. doi: 10.1021/acsami.1c16622. Epub 2021 Nov 4.
Thermoelectric properties of CoSb-based skutterudites are greatly determined by the removal of detrimental impurities, such as (Fe/Co)Sb, (Fe/Co)Sb, and Sb. In this study, we use a facile temperature gradient zone melting (TGZM) method to synthesize high-performance CoSb-based skutterudites by impurity removal. After removing metallic or semimetallic impurities (Fe/Co)Sb, (Fe/Co)Sb, and Sb, the carrier concentration of TGZM-CeFeCoSb can be reduced to 1.21 × 10 cm and the electronic thermal conductivity dramatically reduced to 0.7 W m K at 693 K. Additionally, removing these impurities also effectively reduces the lattice thermal conductivity from 7.2 W m K of cast-CeFeCoSb to 1.02 W m K of TGZM-CeFeCoSb at 693 K. As a consequence, TGZM-CeFeCoSb approaches a high power factor of 11.7 μW cm K and low thermal conductivity of 1.72 W m K at 693 K, leading to a peak of 0.48 at 693 K, which is 10 times higher than that of cast-CeFeCoSb. This study indicates that our facile TGZM method can effectively synthesize high-performance CoSb-based skutterudites by impurity removal and set up a solid foundation for further development.
基于CoSb的方钴矿的热电性能很大程度上取决于有害杂质的去除，例如(Fe/Co)Sb、(Fe/Co)Sb和Sb。在本研究中，我们采用一种简便的温度梯度区熔(TGZM)方法，通过去除杂质来合成高性能的基于CoSb的方钴矿。去除金属或半金属杂质(Fe/Co)Sb、(Fe/Co)Sb和Sb后，TGZM-CeFeCoSb的载流子浓度可降至1.21×10 cm，在693 K时电子热导率大幅降至0.7 W m K。此外，去除这些杂质还能有效地将晶格热导率从铸态CeFeCoSb在693 K时的7.2 W m K降至TGZM-CeFeCoSb在693 K时的1.02 W m K。因此，TGZM-CeFeCoSb在693 K时接近11.7 μW cm K的高功率因数和1.72 W m K的低热导率，在693 K时达到0.48的峰值，这比铸态CeFeCoSb高10倍。本研究表明，我们简便的TGZM方法可以通过去除杂质有效地合成高性能的基于CoSb的方钴矿，并为进一步发展奠定坚实基础。
