Origin of low thermal conductivity in Nb1-xTixFe1.02Sb half-Heusler thermoelectric materials

Hyerin Jeong, Samuel Kimani Kihoi, Joseph Ngugi Kahiu, Hyunji Kim, Juhee Ryu, Kyu Hyoung Lee, Seonghoon Yi, Ho Seong Lee

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7 Citations (Scopus)


Nb1-xTixFe1.02Sb half-Heusler thermoelectric materials were synthesized trough arc melting and subsequent spark plasma sintering (SPS). Doping effect of Ti at Nb-site results in high power factor due to the optimization of hole carrier concentration. Further, the lattice thermal conductivity reduced as the Ti content increased, which mainly resulted from point defects and mass fluctuation by Ti doping as well as coherent nano-scale second phase, Ti-rich and Fe-deficient Ti1.18Fe0.57Sb. For the sample of Nb0.6Ti0.4Fe1.02Sb, a minimum lattice thermal conductivity of ∼2.08 W/mK was obtained. This is attributed to the enhanced phonon scattering at the alternating white and dark lamellar interphase boundaries of (Nb0.6,Ti0.4)FeSb half-Heusler and Nb-doped Ti1.18Fe0.57Sb. A maximum thermoelectric figure of merit, ZT, of ∼0.81 was obtained at 973 K, which is comparable with values previously reported for this system.

Original languageEnglish
Pages (from-to)4175-4181
Number of pages7
JournalJournal of the European Ceramic Society
Issue number7
Publication statusPublished - 2021 Jul

Bibliographical note

Funding Information:
This work was supported by grants from the National Research Foundation (NRF) of Korea (No. 2018R1A41A1022260 ), funded by the Korean government (MSIT) .

Publisher Copyright:
© 2021 Elsevier Ltd

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry


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