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Difference between transition metal cation substitution and Nonstoichiometric addition on nanostructure and thermoelectric performance of complex oxide ceramics.
- Source :
-
Journal of Solid State Chemistry . Sep2019, Vol. 277, p427-433. 7p. - Publication Year :
- 2019
-
Abstract
- This work presents the impact of different methodologies in introducing the transition metal dopants into the thermoelectric Ca 3 Co 4 O 9 ceramics and their resultant nanostructure and electrical transport properties. The polycrystalline ceramics samples are with designed nominal composition of cation substitution of Ca 3 Co 4-x Cu x O 9 (x = 0, 0.01, 0.05, 0.1) and cation non-stoichiometric addition of Ca 3 Co 4 Cu y O 9 (y = 0, 0.01, 0.05, 0.1), respectively. At low-temperature regime, the electrical resistivity decreased to the lowest values for each set of samples, upon the minute Cu doping with x = 0.01, and the electrical resistivity increase with Cu doping level. The Seebeck coefficient presents little change among Ca 3 Co 4-x Cu x O 9 samples. By contrast, the Seebeck coefficient was significantly increased especially in the low-temperature regime in samples of Ca 3 Cu y Co 4 O 9 , when the Cu addition level is over y = 0.05. While the grain size and crystal texture status are almost unchanged among Ca 3 Co 4-x Cu x O 9 samples, non-stoichiometric Cu addition substantially triggered the grain growth, and essentially change the misfit relationship between the Ca 2 CoO 3 and CoO 2 layers within the unit cell. The present study demonstrates a novel approach for hierarchically modifying the structure of complex oxide ceramics to tune their thermoelectric properties through cation non-stoichiometric addition. This work presents that Cation addition in thermoelectric oxide Ca 3 Co 4 Cu y O 9 hierarchically modified the crystal structure from micron to atomic scales. Non-stoichiometric Cu addition substantially triggered the grain growth, modified the incommensurability of two subsystems in unit cell, and resulted in the significantly enhanced Seebeck coefficient. Image 1 • Cation addition in Ca 3 Co 4 Cu y O 9 hierarchically modified the crystal structure. • Cation addition modified the incommensurability of two subsystems in unit cell. • Ca 3 Co 4 Cu y O 9 ceramics are with significantly enhanced Seebeck coefficient. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00224596
- Volume :
- 277
- Database :
- Academic Search Index
- Journal :
- Journal of Solid State Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 138012316
- Full Text :
- https://doi.org/10.1016/j.jssc.2019.06.042