Multiple Converged Conduction Bands in K2Bi8Se13: A Promising Thermoelectric Material with Extremely Low Thermal Conductivity

Yanling Pei, Cheng Chang, Zhe Wang, Meijie Yin, Minghui Wu, Gangjian Tan, Haijun Wu, Yuexing Chen, Lei Zheng, Shengkai Gong, Tiejun Zhu, Xinbing Zhao, Li Huang, Jiaqing He, Mercouri G. Kanatzidis, Li Dong Zhao

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

We report that K2Bi8Se13 exhibits multiple conduction bands that lie close in energy and can be activated through doping, leading to a highly enhanced Seebeck coefficient and a high power factor with elevated temperature. Meanwhile, the large unit cell, complex low symmetry crystal structure, and nondirectional bonding lead to the very low lattice thermal conductivity of K2Bi8Se13, ranging between 0.42 and 0.20 W m-1 K-1 in the temperature interval 300-873 K. Experimentally, we further support the low thermal conductivity of K2Bi8Se13 using phonon velocity measurements; the results show a low average phonon velocity (1605 ms-1), small Young's modulus (37.1 GPa), large Grüneisen parameter (1.71), and low Debye temperature (154 K). A detailed investigation of the microstructure and defects was carried out using electron diffraction and transmission microscopy which reveal the presence of a K2.5Bi8.5Se14 minor phase intergrown along the side of the K2Bi8Se13 phase. The combination of enhanced power factor and low thermal conductivity results in a high ZT value of ∼1.3 at 873 K in electron doped K2Bi8Se13 material.

Original languageEnglish
Pages (from-to)16364-16371
Number of pages8
JournalJournal of the American Chemical Society
Volume138
Issue number50
DOIs
Publication statusPublished - Dec 21 2016

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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    Pei, Y., Chang, C., Wang, Z., Yin, M., Wu, M., Tan, G., Wu, H., Chen, Y., Zheng, L., Gong, S., Zhu, T., Zhao, X., Huang, L., He, J., Kanatzidis, M. G., & Zhao, L. D. (2016). Multiple Converged Conduction Bands in K2Bi8Se13: A Promising Thermoelectric Material with Extremely Low Thermal Conductivity. Journal of the American Chemical Society, 138(50), 16364-16371. https://doi.org/10.1021/jacs.6b09568