Thermoelectric Material SnPb 2 Bi 2 S 6: The 4,4 L Member of Lillianite Homologous Series with Low Lattice Thermal Conductivity

Jingpeng Li, Yiming Zhou, Shiqiang Hao, Tianyan Zhang, Chris Wolverton, Jing Zhao*, Li Dong Zhao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Although the binary sulfides Bi 2 S 3 , PbS, and SnS have attracted extensive interest as thermoelectric materials, no quaternary sulfides containing Sn/Pb/Bi/S elements have been reported. Herein, we report the synthesis of a new quaternary sulfide, SnPb 2 Bi 2 S 6 , which crystallizes in the orthorhombic space group Pnma with unit cell parameters of a = 20.5458(12) Å, b = 4.0925(4) Å, c = 13.3219(10) Å. SnPb 2 Bi 2 S 6 has a lillianite-type crystal structure consisting of two alternately aligned NaCl-type structural motifs separated by a mirror plane of PbS 7 monocapped trigonal prisms. In the lillianite homologous series, SnPb 2 Bi 2 S 6 can be classified as 4,4 L, where the superscripted numbers indicate the maximum numbers of edge-sharing octahedra in the two adjacent NaCl-shaped slabs along the diagonal direction. The obtained SnPb 2 Bi 2 S 6 phase exhibited good thermal stability up to 1000 K and n-type degenerate semiconducting behavior, with a power factor of 3.7 μW cm -1 K -2 at 773 K. Notably, this compound exhibited a very low lattice thermal conductivity of 0.69-0.92 W m -1 K -1 at 300-1000 K. Theoretical calculations revealed that the low thermal conductivity is caused by the complex crystal structure and the related elastic properties of a low Debye temperature, low phonon velocity, and large Grüneisen parameters. A reasonable figure of merit (ZT) of ∼0.3 was obtained at 770 K.

Original languageEnglish (US)
Pages (from-to)1339-1348
Number of pages10
JournalInorganic chemistry
Volume58
Issue number2
DOIs
StatePublished - Jan 22 2019

Funding

This work was funded by Beijing Natural Science Foundation (2182080) and the National Natural Science Foundation of China (51702329 and 51632005). This work was also supported by the Fundamental Research Funds for the Central Universities 06500085 and 06103182. S.H. and C.W. (DFT calculations) acknowledge support from the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award Number DE-SC0014520.

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry

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