High‐Pressure‐Sintering‐Induced Microstructural Engineering for an Ultimate Phonon Scattering of Thermoelectric Half‐Heusler Compounds
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smll.202102045.pdf
Description
Published version
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3.17 MB
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Adobe PDF
Checksum (MD5)
a7e1475b2eebed948b25b8361c34c5fa
Author(s)
He, Ran
Zhu, Taishan
Ying, Pingjun
Chen, Jie
Giebeler, Lars
Kühn, Uta
Grossman, Jeffrey C
Wang, Yumei
Nielsch, Kornelius
Date Issued
2021
Journal
Small
Publisher
Wiley
Citation
He, Ran, Zhu, Taishan, Ying, Pingjun, Chen, Jie, Giebeler, Lars et al. 2021. "High‐Pressure‐Sintering‐Induced Microstructural Engineering for an Ultimate Phonon Scattering of Thermoelectric Half‐Heusler Compounds." Small, 17 (33).
Version
Final published version
Abstract
Thermal management is of vital importance in various modern technologies such as portable electronics, photovoltaics, and thermoelectric devices. Impeding phonon transport remains one of the most challenging tasks for improving the thermoelectric performance of certain materials such as half-Heusler compounds. Herein, a significant reduction of lattice thermal conductivity (κL ) is achieved by applying a pressure of ≈1 GPa to sinter a broad range of half-Heusler compounds. Contrasting with the common sintering pressure of less than 100 MPa, the gigapascal-level pressure enables densification at a lower temperature, thus greatly modifying the structural characteristics for an intensified phonon scattering. A maximum κL reduction of ≈83% is realized for HfCoSb from 14 to 2.5 W m-1 K-1 at 300 K with more than 95% relative density. The realized low κL originates from a remarkable grain-size refinement to below 100 nm together with the abundant in-grain defects, as determined by microscopy investigations. This work uncovers the phonon transport properties of half-Heusler compounds under unconventional microstructures, thus showing the potential of high-pressure compaction in advancing the performance of thermoelectric materials.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
https://doi.org/10.1002/SMLL.202102045
