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http://hdl.handle.net/10773/26371
Title: | Significant enhancement of the thermoelectric performance in Ca3Co4O9 thermoelectric materials through combined strontium substitution and hot-pressing process |
Author: | Torres, M. A. Costa, F. M. Flahaut, D. Touati, K. Rasekh, Sh. Ferreira, N. M. Allouche, J. Depriester, M. Madre, M. A. Kavaleuski, A. Diez, J. C. Sotelo, A. |
Keywords: | Ceramicss Electrical propertie Hot-pressing Oxides Texture |
Issue Date: | Apr-2019 |
Publisher: | Elsevier |
Abstract: | This work explores the possibilities for a further enhancement of the thermoelectric properties of Ca3Co4O9 by Sr-doping combined with hot-pressing. Modified hot-pressing process resulted in highly-textured and dense ceramics. Sr-doping significantly improves electrical properties, resulting in extremely large power factor (1.2 mW/K2m at 800 °C) due to simultaneous electrical resistivity decrease and Seebeck coefficient increase. The main effect on cumulative electrical performance is provided by the Seebeck coefficient, reaching 270μV/K at 800 °C. XPS revealed relatively high average cobalt oxidation state at room temperature (+3.3), compared to materials produced by conventional sintering. The results of combined XPS and Auger electron spectroscopy emphasize the importance of high densification in Ca3Co4O9-based ceramics for preventing phase decomposition and interaction with CO2 and moisture. Still, despite the exceptional electrical performance, the calculated figure-of-merit (estimated as 0.29 at 800 °C) is around the best reported in the literature due to a high thermal conductivity (4.4 W/K m at room temperature). |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/26371 |
DOI: | 10.1016/j.jeurceramsoc.2018.12.049 |
ISSN: | 0955-2219 |
Appears in Collections: | CICECO - Artigos I3N-FSCOSD - Artigos |
Files in This Item:
File | Description | Size | Format | |
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JECS_39_2019_1186_peer_rev.pdf | 858.51 kB | Adobe PDF | View/Open |
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