Cryogenic thermoelectric enhancements in SbCl3-doped porous Bi0.85Sb0.15 alloys

作者：Wang, Jian; Luo, Feng; Zhu, Can; Wang, Jiafu; He, Xiong; Zhang, Yan; Liu, Hongxia^*; Sun, Zhigang^*

来源：Journal of Materials Chemistry C, 2023, 11(12): 4056-4069.

DOI：10.1039/d3tc00020f

• BISMUTH-ANTIMONY TELLURIDE
• LOW THERMAL-CONDUCTIVITY
• TRANSPORT-PROPERTIES
• PERFORMANCE
• DEPENDENCE
• FIGURE
• MERIT
• STATE

In this work, porous Bi0.85Sb0.15/x vol% SbCl3 (x = 0, 0.5, 1, 1.5, and 2) materials were prepared by melt-spinning combined with hot pressing and annealing, and the effects of SbCl3 doping as well as the porous structure on their cryogenic thermoelectric performance were investigated. It is found that the nano/microscale porous structure is formed due to SbCl3 sublimation during annealing, and meanwhile a small amount of SbCl3 is doped into the Bi0.85Sb0.15 matrix simultaneously. The carrier concentration is reduced as a consequence of Cl doping, leading to a well-maintained PF (66 mu W cm(-1) K-2) and a 27% reduction in kappa(ele) + kappa(bip). A low kappa(L) of 0.71 W m(-1) K-1 is obtained for the intense phonon scattering due to the porous structure. Thus, the maximum ZT value of 0.45 at 180 K is achieved for the Bi0.85Sb0.15/1 vol% SbCl3 sample, and is increased by 45% compared with that of the Bi0.85Sb0.15 matrix. Under an external magnetic field, the enhancement of S compensates for the decrease in the electrical conductivity, resulting in an unchanged PF. With the suppression of kappa(ele) + kappa(bip) by the magnetic field and the reduction of kappa(L) by the porous structure, a low kappa(tot) of 1.56 W m(-1) K-1 under 1 T is obtained. Finally, the maximum ZT value of 0.64 at 220 K under 1 T is achieved for the Bi0.85Sb0.15/1 vol% SbCl3 sample, and is increased by 106% compared with that of the Bi0.85Sb0.15 matrix. This work demonstrates that SbCl3 doping combined with a porous structure can synergistically regulate the electronic and thermal transport properties of the Bi0.85Sb0.15 alloy, and can further promote its cryogenic thermoelectric performance.

• 单位
  武汉理工大学