Farahi, Nader and Stiewe, Christian and Truong, Dao Y Nhi and Shi, Yixuan and Salamon, Soma and Landers, Joachim and Eggert, Benedikt and Wende, Heiko and de Boor, Johannes and Kleinke, Holger and Müller, Eckhard (2019) Effects of Ta Substitution on the Microstructure and Transport Properties of Hf-Doped NbFeSb Half-Heusler Thermoelectric Materials. ACS Applied Energy Materials. American Chemical Society (ACS). doi: 10.1021/acsaem.9b01711. ISSN 2574-0962.
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Abstract
This investigation demonstrates the effect of partial substitutions of Nb by refractory Ta on the microstructure and thermoelectric properties of Hf-doped NbFeSb materials. All the synthesized samples show a heavily doped semiconducting character with the electrical conductivity higher than 3500 Ω–1 cm–1 at 326 K. Furthermore, the samples containing Ta display consistently lower (∼10–13%) thermal conductivity of ∼7 W m–1 K–1 at 350 K compared to a value of ∼8 W m–1 K–1 at the same temperature for the nonsubstituted sample. The vivid impact of Ta substitutions on reducing the lattice thermal conductivity of NbFeSb based materials is chiefly due to the lattice disorder originating from the mass difference between Ta and Nb atoms, resulting in ∼28% reduction in lattice thermal conductivity of the Nb0.73Hf0.12Ta0.15FeSb sample at 350 K compared to the nonsubstituted sample. The results of our Mößbauer spectroscopy measurements exclude the possibility of mixed Fe occupancies. Although magnetic properties were not strongly modified by the Ta substitution, Nb0.83Hf0.12Ta0.05FeSb shows a magnetic phase transition at ∼150 K, which is not observed in Nb0.88Hf0.12FeSb. This could be caused by extrinsic defects and microstructure induced by Ta addition. All samples exhibit a similar maximum dimensionless figure of merit value, zTmax, of ∼0.75 at 800 K, which is comparable to the high efficiency materials previously reported in this system and makes them potential candidates to be utilized as p-type legs in half-Heusler based thermoelectric generators (TEG).
Item URL in elib: | https://elib.dlr.de/130632/ | ||||||||||||||||||||||||||||||||||||||||||||||||
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Document Type: | Article | ||||||||||||||||||||||||||||||||||||||||||||||||
Title: | Effects of Ta Substitution on the Microstructure and Transport Properties of Hf-Doped NbFeSb Half-Heusler Thermoelectric Materials | ||||||||||||||||||||||||||||||||||||||||||||||||
Authors: |
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Date: | 4 November 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||
Journal or Publication Title: | ACS Applied Energy Materials | ||||||||||||||||||||||||||||||||||||||||||||||||
Refereed publication: | Yes | ||||||||||||||||||||||||||||||||||||||||||||||||
Open Access: | Yes | ||||||||||||||||||||||||||||||||||||||||||||||||
Gold Open Access: | No | ||||||||||||||||||||||||||||||||||||||||||||||||
In SCOPUS: | Yes | ||||||||||||||||||||||||||||||||||||||||||||||||
In ISI Web of Science: | Yes | ||||||||||||||||||||||||||||||||||||||||||||||||
DOI: | 10.1021/acsaem.9b01711 | ||||||||||||||||||||||||||||||||||||||||||||||||
Publisher: | American Chemical Society (ACS) | ||||||||||||||||||||||||||||||||||||||||||||||||
ISSN: | 2574-0962 | ||||||||||||||||||||||||||||||||||||||||||||||||
Status: | Published | ||||||||||||||||||||||||||||||||||||||||||||||||
Keywords: | Thermoelectric; half-Heusler; antimonide; alloying; doping | ||||||||||||||||||||||||||||||||||||||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||||||||||||||||||||||||||||||||||||||||||||
HGF - Program: | Transport | ||||||||||||||||||||||||||||||||||||||||||||||||
HGF - Program Themes: | Road Transport | ||||||||||||||||||||||||||||||||||||||||||||||||
DLR - Research area: | Transport | ||||||||||||||||||||||||||||||||||||||||||||||||
DLR - Program: | V ST Straßenverkehr | ||||||||||||||||||||||||||||||||||||||||||||||||
DLR - Research theme (Project): | V - NGC Antriebssystem und Energiemanagement (old) | ||||||||||||||||||||||||||||||||||||||||||||||||
Location: | Köln-Porz | ||||||||||||||||||||||||||||||||||||||||||||||||
Institutes and Institutions: | Institute of Materials Research > Thermoelectric Materials and Systems | ||||||||||||||||||||||||||||||||||||||||||||||||
Deposited By: | Yasseri, Mohammad | ||||||||||||||||||||||||||||||||||||||||||||||||
Deposited On: | 15 Nov 2019 15:21 | ||||||||||||||||||||||||||||||||||||||||||||||||
Last Modified: | 04 Nov 2020 03:00 |
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