Approaching the minimum lattice thermal conductivity of p-type SnTe thermoelectric materials by Sb and Mg alloying

Tiezheng Fu; Jiazhan Xin; Tiejun Zhu; Jiajun Shen; Teng Fang; Xinbing Zhao

doi:10.1016/j.scib.2019.06.007

Approaching the minimum lattice thermal conductivity of p-type SnTe thermoelectric materials by Sb and Mg alloying

Sci Bull (Beijing). 2019 Jul 30;64(14):1024-1030. doi: 10.1016/j.scib.2019.06.007. Epub 2019 Jun 6.

Authors

Tiezheng Fu¹, Jiazhan Xin¹, Tiejun Zhu², Jiajun Shen¹, Teng Fang¹, Xinbing Zhao³

Affiliations

¹ State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
² State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: zhutj@zju.edu.cn.
³ State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: zhaoxb@zju.edu.cn.

PMID: 36659802
DOI: 10.1016/j.scib.2019.06.007

Abstract

SnTe, as the nontoxic analogue to high-performance PbTe thermoelectric material, has captured the worldwide interest recently. Many triumphant instances focus on the strategies of band convergence, resonant doping, and nano-precipitates phonon scattering. Herein, the p-type SnTe-based materials Sn_0.85-_xSb_0.15Mg_xTe (x = 0-0.10) are fabricated and a combined effect of Sb and Mg is investigated. Sb alloying tunes the hole carrier concentration of SnTe and decreases the lattice thermal conductivity. Mg alloying leads to a nearly hundredfold rise of disorder parameter due to the large mass and strain fluctuations, and as a consequence the lattice thermal conductivity decreases further down to ∼0.64 W m^-1 K^-1 at 773 K, close to the theoretical minimum of the lattice thermal conductivity (∼0.50 W m^-1 K^-1) of SnTe. In conjunction with the enhancement of the Seebeck coefficient caused by band convergence due to Mg alloying, the maximum zT_max reaches ∼1.02 and the device zT_device of ∼0.50 at 773 K for Sn_0.79Sb_0.15Mg_0.06Te, suggesting this SnTe-based composition has a promising potential in intermediate temperature thermoelectric applications.

Keywords: Band convergence; Point defect scattering; Thermoelectric materials; Tin telluride.