中国物理B ›› 2024, Vol. 33 ›› Issue (5): 57201-057201.doi: 10.1088/1674-1056/ad2d57

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Rational design and synthesis of Cr1-xTe/Ag2Te composites for solid-state thermoelectromagnetic cooling near room temperature

Xiaochen Sun(孙笑晨)1, Chenghao Xie(谢承昊)1, Sihan Chen(陈思汗)1, Jingwei Wan(万京伟)1,2, Gangjian Tan(谭刚健)1,†, and Xinfeng Tang(唐新峰)1,‡   

  1. 1 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China;
    2 International School of Materials Science & Engineering, Wuhan University of Technology, Wuhan 430070, China
  • 收稿日期:2024-01-28 修回日期:2024-02-20 接受日期:2024-02-27 出版日期:2024-05-20 发布日期:2024-05-20
  • 通讯作者: Gangjian Tan, Xinfeng Tang E-mail:gtan@whut.edu.cn;tangxf@whut.edu.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant No. 2019YFA0704900) and the National Natural Science Foundation of China (Grant No. 52171221).

Rational design and synthesis of Cr1-xTe/Ag2Te composites for solid-state thermoelectromagnetic cooling near room temperature

Xiaochen Sun(孙笑晨)1, Chenghao Xie(谢承昊)1, Sihan Chen(陈思汗)1, Jingwei Wan(万京伟)1,2, Gangjian Tan(谭刚健)1,†, and Xinfeng Tang(唐新峰)1,‡   

  1. 1 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China;
    2 International School of Materials Science & Engineering, Wuhan University of Technology, Wuhan 430070, China
  • Received:2024-01-28 Revised:2024-02-20 Accepted:2024-02-27 Online:2024-05-20 Published:2024-05-20
  • Contact: Gangjian Tan, Xinfeng Tang E-mail:gtan@whut.edu.cn;tangxf@whut.edu.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2019YFA0704900) and the National Natural Science Foundation of China (Grant No. 52171221).

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摘要： Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling. These two properties, however, hardly coexist in single phase materials except previously reported hexagonal Cr$_{1-x}$Te half metal where a relatively high magnetic entropy change $(-\Delta S_{\rm M})$ of $\sim 2.4 $ J$\cdot $kg$^{-1}\cdot$K$^{-1}$ @ 5 T and a moderate thermoelectric figure of merit (ZT) of $\sim 1.2\times 10^{-2}$ @ 300 K are simultaneously recorded. Herein we aim to increase the thermoelectric performance of Cr$_{1-x}$Te by compositing with semiconducting Ag$_{2}$Te. It is discovered that the in-situ synthesis of Cr$_{1-x}$Te/Ag$_{2}$Te composites by reacting their constitute elements above melting temperatures is unsuccessful because of strong phase competition. Specifically, at elevated temperatures ($T > 800 $ K), Cr$_{1-x}$Te has a much lower deformation energy than Ag$_{2}$Te and tends to become more Cr-deficient by capturing Te from Ag$_{2}$Te. Therefore, Ag is insufficiently reacted and as a metal it deteriorates ZT. We then rationalize the synthesis of Cr$_{1-x}$Te/Ag$_{2}$Te composites by ex-situ mix of the pre-prepared Cr$_{1-x}$Te and Ag$_{2}$Te binary compounds followed by densification at a low sintering temperature of 573 K under a pressure of 3.5 GPa. We show that by compositing with 7 mol% Ag$_{2}$Te, the Seebeck coefficient of Cr$_{1-x}$Te is largely increased while the lattice thermal conductivity is considerably reduced, leading to 72% improvement of ZT. By comparison, $-\Delta S_{\rm M}$ is only slightly reduced by 10% in the composite. Our work demonstrates the potential of Cr$_{1-x}$Te/Ag$_{2}$Te composites for thermoelectromagnetic cooling.

关键词: thermoelectromagnetic cooling, thermoelectric, magnetocaloric, composite, chromium telluride

Abstract: Materials with both large magnetocaloric response and high thermoelectric performance are of vital importance for all-solid-state thermoelectromagnetic cooling. These two properties, however, hardly coexist in single phase materials except previously reported hexagonal Cr$_{1-x}$Te half metal where a relatively high magnetic entropy change $(-\Delta S_{\rm M})$ of $\sim 2.4 $ J$\cdot $kg$^{-1}\cdot$K$^{-1}$ @ 5 T and a moderate thermoelectric figure of merit (ZT) of $\sim 1.2\times 10^{-2}$ @ 300 K are simultaneously recorded. Herein we aim to increase the thermoelectric performance of Cr$_{1-x}$Te by compositing with semiconducting Ag$_{2}$Te. It is discovered that the in-situ synthesis of Cr$_{1-x}$Te/Ag$_{2}$Te composites by reacting their constitute elements above melting temperatures is unsuccessful because of strong phase competition. Specifically, at elevated temperatures ($T > 800 $ K), Cr$_{1-x}$Te has a much lower deformation energy than Ag$_{2}$Te and tends to become more Cr-deficient by capturing Te from Ag$_{2}$Te. Therefore, Ag is insufficiently reacted and as a metal it deteriorates ZT. We then rationalize the synthesis of Cr$_{1-x}$Te/Ag$_{2}$Te composites by ex-situ mix of the pre-prepared Cr$_{1-x}$Te and Ag$_{2}$Te binary compounds followed by densification at a low sintering temperature of 573 K under a pressure of 3.5 GPa. We show that by compositing with 7 mol% Ag$_{2}$Te, the Seebeck coefficient of Cr$_{1-x}$Te is largely increased while the lattice thermal conductivity is considerably reduced, leading to 72% improvement of ZT. By comparison, $-\Delta S_{\rm M}$ is only slightly reduced by 10% in the composite. Our work demonstrates the potential of Cr$_{1-x}$Te/Ag$_{2}$Te composites for thermoelectromagnetic cooling.

Key words: thermoelectromagnetic cooling, thermoelectric, magnetocaloric, composite, chromium telluride

中图分类号:  (Thermoelectric and thermomagnetic effects)

  • 72.15.Jf
73.50.Lw (Thermoelectric effects)