High-performance and stable AgSbTe2-based thermoelectric materials for near room temperature applications

doi:10.1016/j.jmat.2022.07.005

Journal of Materiomics

Volume 8, Issue 6, November 2022, Pages 1095-1103

https://doi.org/10.1016/j.jmat.2022.07.005 Get rights and content

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Highlights

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AgSbTe₂-based ternary chalcogenides can be stabilized for service below 473 K.
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Phase pure Ag_0.9Sb_1.1Te_2.1 is verified by comprehensive structural characterizations from macroscale to sub-nanometer scale.
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The decomposition threshold and decomposition mechanism of Ag_0.9Sb_1.1Te_2.1 are discussed.
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The average zT of Ag_0.9Sb_1.1Te_2.1 at 300–473 K reaches 0.84.

Abstract

AgSbTe₂-based ternary chalcogenides show excellent thermoelectric performance at low- and middle-temperature ranges, yet their practical applications are greatly limited by their intrinsic poor thermodynamic stability. In this work, we demonstrate that AgSbTe₂-based ternary chalcogenides can be stabilized for service below their decomposition threshold. A series of Ag_xSb_2-xTe_3-x (x = 1.0, 0.9, 0.8 and 0.7) samples have been prepared by the melt-quenching method. Among them, phase pure Ag_0.9Sb_1.1Te_2.1 is verified by comprehensive structural characterizations from macroscale by X-ray diffraction to microscale by energy-dispersive spectroscopy and then to sub-nanometer scale by atom probe tomography. This composition is further chosen for the stability investigation. The decomposition threshold of Ag_0.9Sb_1.1Te_2.1 appears around 473 K. Below this temperature, the chemical compositions and thermoelectric properties are barely changed even after 720 h annealing at 473 K. The figure-of-merit (zT) value of Ag_0.9Sb_1.1Te_2.1 below the decomposition threshold is very competitive for real applications even compared with Bi₂Te₃-based alloys. The average zT of Ag_0.9Sb_1.1Te_2.1 at 300–473 K reaches 0.84, which is higher than most other thermoelectric materials in a similar temperature range, promising applications in miniaturized refrigeration and power generation near room temperature.

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Yi Wu received his B.S. in materials science and engineering from Kunming University of Science and Technology. He is currently studying for a Master degree at Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS). His current research mainly focuses on AgSbTe₂-based thermoelectric materials.

Pengfei Qiu is a professor at SICCAS. He received his Ph.D. degree in Materials Chemistry and Physics from Shanghai Institute of Ceramics, Chinese Academy of Sciences in 2011 and Bachelor's degree BS in Materials science and Engineering from Wuhan University of Technology in 2006. His research interests are in advanced thermoelectric semiconductors, from synthesizing the materials to understanding the underlying physics and chemistry.

Yuan Yu received his Ph.D. degree in materials science and engineering from Hefei University of Technology in 2017. He was a visiting student at the Institute of Physics (IA) of RWTH Aachen University from November 2015 to May 2017. He then joined Prof. Matthias Wuttig's group as a postdoctoral researcher since 2018. His primary scientific interests include the design of thermoelectric materials by understanding their chemical bonding mechanisms (Metavalent Bonding), as well as the characterization of thermoelectric materials using (transmission) electron back-scatter diffraction and atom probe tomography.

: Peer review under responsibility of The Chinese Ceramic Society.