Compositional tuning of ZrNiSn half-Heusler alloys: Thermoelectric characteristics and performance analysis

Nagendra S. Chauhan, Sivaiah Bathula, Avinash Vishwakarma, Ruchi Bhardwaj, Kishor Kumar Johari, Bhasker Gahtori, Muthiah Saravanan, Ajay Dhar

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


Nanostructuring has rejuvenated great interest in thermoelectric (TE) based power generation by enabling enhanced performance in nano-grained TE materials over their bulk counterparts. In ZrNiSn based half-Heusler (HH), a promising n-type TE materials, we examine the prospects of nanostructuring by synthesizing nano-crystalline iso-electronically substituted n-type Zr1-xHfxNiSn HH alloys to achieve a state-of-the-art TE figure-of-merit ZT ∼ 1.2 at 873 K, which is ∼20% higher than its bulk counterparts and corresponds to high conversion efficiency of ∼9% with output power density ∼7 Wcm−2, estimated using cumulative temperature dependence model. Enhanced phonon scattering at nano-scale grain boundaries and crystal defects, arising from nanostructuring and mass defect fluctuation in Hf substituted ZrNiSn alloys resulted in significantly reduced thermal conductivity. It was found that the partial substitution at Zr site with its heavier homologue Hf causes variation in the carrier effective mass and carrier concentration, which at lower Hf concentration results in an enhancement in the power factor.

Original languageEnglish
Pages (from-to)105-112
Number of pages8
JournalJournal of Physics and Chemistry of Solids
Publication statusPublished - 2018 Dec
Externally publishedYes


  • Efficiency
  • Half-heusler
  • Isoelectronic
  • Mid-temperature
  • Nanostructuring
  • Waste heat recovery

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics


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