Improvement of Thermoelectric Properties via Texturation Using a Magnetic Slip Casting Process-The Illustrative Case of CrSi2

Sylvain Le Tonquesse*, Wenhao Zhang, Bhuvanesh Srinivasan, Bruno Fontaine, Takanobu Hiroto, Takao Mori, Jean François Halet, David Berthebaud, Tohru S. Suzuki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Transition metal silicides constitute a promising class of inexpensive and nontoxic thermoelectric materials showing competitive properties. This article reports an efficient process to synthesize highly textured polycrystalline CrSi2 by performing slip casting under a strong magnetic field. The crystallographic texture of spark plasma sintered samples, characterized by electron backscattered and X-ray diffraction techniques, showed a fiber texture symmetry with the c-axis of hexagonal CrSi2 aligning preferentially along the magnetic field direction. The thermoelectric properties measured both parallel and perpendicular to the c-axis texture direction showed a large anisotropy. In particular, a significantly higher Seebeck coefficient was measured, ∥c, reaching a maximum value of 200 μV K-1 at 650 K, inducing a power factor ∥c twice higher than ⊥c with an average value of 2.2 mW m-1 K-2. Density functional theory and transport property calculations revealed that an anisotropic two-band model can explain the higher thermoelectric property along the c-axis direction, which can be traced to Cr-Cr bonding interactions along this direction. The estimated thermoelectric figure of merit ZT∥c was improved to 0.20 at 773 K. This is 50% higher than that measured for randomly oriented samples and comparable to that observed for single crystals. Such a performance boost can certainly be reiterated for other types of thermoelectric materials using the efficient magnetic slip-casting process reported in this article.

Original languageEnglish
Pages (from-to)1143-1156
Number of pages14
JournalChemistry of Materials
Volume34
Issue number3
DOIs
Publication statusPublished - 2022 Feb 8
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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