Abnormal Grain Growth as a Method To Enhance the Thermoelectric Performance of Nb-Doped Strontium Titanate Ceramics

Driven by the need for high-temperature n-type thermoelectrics for energy-harvesting sectors, SrTi0.8Nb0.2O3±δ ceramics are prepared here from powders with average particle sizes of 270 and 800 nm by the conventional sintering in air at 1450 °C and further in H2/N2 at 1400 °C. In contrast to coarse...

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Bibliographic Details
Published in:ACS sustainable chemistry & engineering 2018-12, Vol.6 (12), p.15988-15994
Main Authors: Tkach, Alexander, Resende, João, Saravanan, K. Venkata, Costa, Maria Elisabete, Diaz-Chao, Pablo, Guilmeau, Emmanuel, Okhay, Olena, Vilarinho, Paula M
Format: Article
Language:English
Subjects:
Chemical Sciences
Cristallography
Inorganic chemistry
Material chemistry
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Summary:Driven by the need for high-temperature n-type thermoelectrics for energy-harvesting sectors, SrTi0.8Nb0.2O3±δ ceramics are prepared here from powders with average particle sizes of 270 and 800 nm by the conventional sintering in air at 1450 °C and further in H2/N2 at 1400 °C. In contrast to coarse particle powders, the use of fine particle powders under these conditions leads to abnormal grain growth and thereby bimodal grain size distribution in SrTi0.8Nb0.2O3±δ ceramics. As a result, a 3-fold increase in the thermoelectric figure of merit to 0.36 at 970 K is achieved, thus establishing the record value for bulk Nb-doped strontium titanate up to this temperature.
ISSN:2168-0485
2168-0485
DOI:10.1021/acssuschemeng.8b03875