Year: 2020
Type: article
Abstract: The thermoelectric figure of merit ZT, which is defined using electrical conductivity, Seebeck coefficient, thermal conductivity, and absolute temperature T, has been widely used as a simple estimator of the conversion efficiency of a thermoelectric heat engine. When material properties are constant or slowly varying with T, a higher ZT ensures a higher maximum conversion efficiency of thermoelectric materials. However, as material properties can vary strongly with T, efficiency predictions based on ZT can be inaccurate, especially for wide-temperature applications. Moreover, although ZT values continue to increase, there has been no investigation of the relationship between ZT and the efficiency in the higher ZT regime. In this paper, we report a counterintuitive situation by comparing two materials: although one material has a higher ZT value over the whole operating temperature range, its maximum conversion efficiency is smaller than that of the other. This indicates that, for material comparisons, the evaluation of exact efficiencies as opposed to a simple comparison of ZTs is necessary in certain cases.
Source: Applied Physics Letters
DOI: 10.1063/5.0003749
Authors: Byungki Ryu, Jaywan Chung, Eun-Ae Choi, Pawel Ziolkowski, Eckhard Müller, SuDong Park
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Funders: Deutsches Zentrum für Luft- und Raumfahrt, Ministry of Trade, Industry and Energy, Korea Electrotechnology Research Institute, National Research Council of Science and Technology, Ministry of Science and ICT, South Korea, Korea Institute of Materials Science, Korea Institute of Energy Technology Evaluation and Planning
OpenAlex ID: W3003734946