| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
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Energy Materials for Sustainable Development
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| Presentation Title |
Tuning the Thermoelectric Performance of CaMnO3-based Ceramics by Controlled Exsolution and Micro-structuring
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| Author(s) |
Nikola Kanas, Benjamin A. D. Williamson, Richard Hinterding, Mari-Ann Einarsrud, Sverre Magnus Selbach, Armin Feldhoff, Kjell Wiik |
| On-Site Speaker (Planned) |
Nikola Kanas |
| Abstract Scope |
In this work we extend the study on the previously reported CaMnO3/CaMn2O4 composites, focusing on the effect of microstructure and composition on the thermoelectric properties. Single phase compositions were produced in reducing atmosphere and subsequently fully densified by spark plasma sintering in vacuum. Annealing in air at 1340 °C between 1 and 8 hours activated redox exsolution and resulted in a variation in microstructure of materials with 10 and 15 vol% CaMn2O4. The nature of the CaMnO3-δ-CaMn2O4 interface was analyzed by scanning and transmission electron microscopies followed by a theoretical approach based on density functional theory.
The highest electrical and lowest thermal conductivities were obtained for composite CMO10%8h, reaching 49 S·cm-1 at 900 °C and 0.56 W·m-1K-1 at 700 ºC, respectively. However, the highest zT was observed for composite CMO15%8h reaching 0.11 at 900 °C, due to the enhanced power factor above 700 °C. |