中国物理B ›› 2020, Vol. 29 ›› Issue (6): 67201-067201.doi: 10.1088/1674-1056/ab84cd

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Significant role of nanoscale Bi-rich phase in optimizing thermoelectric performance of Mg3Sb2

Yang Wang(王杨), Xin Zhang(张忻), Yan-Qin Liu(刘燕琴), Jiu-Xing Zhang(张久兴), Ming Yue(岳明)   

  1. 1 Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China;
    2 School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China
  • 收稿日期:2019-12-20 修回日期:2020-03-23 出版日期:2020-06-05 发布日期:2020-06-05
  • 通讯作者: Xin Zhang E-mail:zhxin@bjut.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51371010, 51572066, and 50801002), the Beijing Municipal Natural Science Foundation, China (Grant No. 2112007), the Fundamental Research Funds for the Central Universities (Grant No. PXM2019-014204-500032), and the Science Fund from the Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology, China (Grant No. LabASP-2018-09).

Significant role of nanoscale Bi-rich phase in optimizing thermoelectric performance of Mg3Sb2

Yang Wang(王杨)1, Xin Zhang(张忻)1, Yan-Qin Liu(刘燕琴)1, Jiu-Xing Zhang(张久兴)2, Ming Yue(岳明)1   

  1. 1 Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China;
    2 School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China
  • Received:2019-12-20 Revised:2020-03-23 Online:2020-06-05 Published:2020-06-05
  • Contact: Xin Zhang E-mail:zhxin@bjut.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51371010, 51572066, and 50801002), the Beijing Municipal Natural Science Foundation, China (Grant No. 2112007), the Fundamental Research Funds for the Central Universities (Grant No. PXM2019-014204-500032), and the Science Fund from the Advanced Space Propulsion Laboratory of BICE and Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology, China (Grant No. LabASP-2018-09).

摘要: Mg3Sb1.5Bi0.5-based alloys have received much attention, and current reports on this system mainly focus on the modulation of doping. However, there lacks the explanation for the choice of Mg3Sb1.5Bi0.5 as matrix. Here in this work, the thermoelectric properties of Mg3Sb2-xBix (0.4 ≤ x ≤ 0.55) compounds are systematically investigated by using the first principles calculation combined with experiment. The calculated results show that the band gap decreases after Bi has been substituted for Sb site, which makes the thermal activation easier. The maximum figure of merit (ZT) is 0.27 at 773 K, which is attributed to the ultra-low thermal conductivity 0.53 W·m-1·K-1 for x=0.5. The large mass difference between Bi and Sb atoms, the lattice distortion induced by substituting Bi for Sb, and the nanoscale Bi-rich particles distributed on the matrix are responsible for the reduction of thermal conductivity. The introduction of Bi into Mg3Sb2-based materials plays a vital role in regulating the transport performance of thermoelectric materials.

关键词: first principles calculations, nanoscale Bi-rich phase, Mg3Sb2, thermoelectric performance

Abstract: Mg3Sb1.5Bi0.5-based alloys have received much attention, and current reports on this system mainly focus on the modulation of doping. However, there lacks the explanation for the choice of Mg3Sb1.5Bi0.5 as matrix. Here in this work, the thermoelectric properties of Mg3Sb2-xBix (0.4 ≤ x ≤ 0.55) compounds are systematically investigated by using the first principles calculation combined with experiment. The calculated results show that the band gap decreases after Bi has been substituted for Sb site, which makes the thermal activation easier. The maximum figure of merit (ZT) is 0.27 at 773 K, which is attributed to the ultra-low thermal conductivity 0.53 W·m-1·K-1 for x=0.5. The large mass difference between Bi and Sb atoms, the lattice distortion induced by substituting Bi for Sb, and the nanoscale Bi-rich particles distributed on the matrix are responsible for the reduction of thermal conductivity. The introduction of Bi into Mg3Sb2-based materials plays a vital role in regulating the transport performance of thermoelectric materials.

Key words: first principles calculations, nanoscale Bi-rich phase, Mg3Sb2, thermoelectric performance

中图分类号:  (Thermoelectric and thermomagnetic effects)

  • 72.20.Pa
73.50.Lw (Thermoelectric effects)