Chauhan, Nagendra S. and Bathula, Sivaiah and Gahtori, Bhasker and Mahanti, Subhendra D. and Bhattacharya, Amrita and Vishwakarma, Avinash and Bhardwaj, Ruchi and Singh, Vidya Nand and Dhar, Ajay (2019) Compositional Tailoring for Realizing High Thermoelectric Performance in Hafnium-Free n-Type ZrNiSn Half-Heusler Alloys. ACS Applied Materials and Interfaces, 11 (51). 47830-47836. ISSN 1944-8244
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Abstract
Compositional tailoring enables fine-tuning of thermoelectric (TE) transport parameters by synergistic modulation of electronic and vibrational properties. In the present work, the aspects of compositionally tailored defects have been explored in ZrNiSn-based half-Heusler (HH) TE materials to achieve high TE performance and cost effectiveness in n-type Hf-free HH alloys. In off-stoichiometric Ni-rich ZrNi1+xSn alloys in a low Ni doping limit (x < 0.1), excess Ni induces defects (Ni/vacancy antisite + interstitials), which tend to cause band structure modification. In addition, the structural similarity of HH and full-Heusler (FH) compounds and formation energetics lead to an intrinsic phase segregation of FH nanoscale precipitates that are coherently dispersed within the ZrNiSn HH matrix as nanoclusters. A consonance was achieved experimentally between these two competing mechanisms for optimal HH composition having both FH precipitates and Ni/vacancy antisite defects in the HH matrix by elevating the sintering temperature up to the solubility limit range of the ZrNiSn system. Defect-mediated optimization of electrical and thermal transport via carrier concentration tuning, energy filtering, and possibly all scale-hierarchical architecture resulted in a maximum ZT approximate to 1.1 at 873 K for the optimized ZrNi1.03Sn composition. Our findings highlight the realistic prospect of enhancing TE performance via compositional engineering approach for wide applications of TE.
| Item Type: | Article |
|---|---|
| Additional Information: | Copyright for this article belongs to M/s American Chemical Society. |
| Subjects: | Materials Science Nanoscience/ Nanotechnology |
| Divisions: | UNSPECIFIED |
| Depositing User: | Mr. Yogesh Joshi |
| Date Deposited: | 19 Aug 2026 11:35 |
| Last Modified: | 19 Aug 2026 11:35 |
| URI: | https://npl.csircentral.net/id/eprint/4356 |
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