Grain-by-grain compositional variations and interstitial metals - a new route towards achieving high performance in Half-Heusler thermoelectrics
| Autor: | Barczak, Sonia, Halpin, John, Buckman, Jim, Decourt, Rodolphe, Pollet, Michaël, Smith, Ronald, MacLaren, Donald, Bos, Jan-Willem |
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| Přispěvatelé: | Institute of Chemical Sciences and Centre for Advanced Energy Storage and Recovery, Heriot-Watt University [Edinburgh] (HWU), SUPA School of Physics and Astronomy [Glasgow], University of Glasgow, Institute of Petroleum Engineering, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ISIS Facility, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | ACS Applied Materials & Interfaces ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2018, 10 (5), pp.4786-4793. ⟨10.1021/acsami.7b14525⟩ |
| ISSN: | 1944-8244 1944-8252 |
| DOI: | 10.1021/acsami.7b14525⟩ |
| Popis: | International audience; Half-Heusler alloys based on TiNiSn are promising thermoelectric materials characterized by large power factors and good mechanical and thermal stabilities, but they are limited by large thermal conductivities. A variety of strategies have been used to disrupt their thermal transport, including alloying with heavy, generally expensive, elements and nanostructuring, enabling figures of merit, ZT ≥ 1 at elevated temperatures (>773 K). Here, we demonstrate an alternative strategy that is based around the partial segregation of excess Cu leading to grain-by-grain compositional variations, the formation of extruded Cu “wetting layers” between grains, and—most importantly—the presence of statistically distributed interstitials that reduce the thermal conductivity effectively through point-defect scattering. Our best TiNiCuySn (y ≤ 0.1) compositions have a temperature-averaged ZTdevice = 0.3–0.4 and estimated leg power outputs of 6–7 W cm–2 in the 323–773 K temperature range. This is a significant development as these materials were prepared using a straightforward processing method, do not contain any toxic, expensive, or scarce elements, and are therefore promising candidates for large-scale production. |
| Databáze: | OpenAIRE |
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