Redox engineering of strontium titanate-based thermoelectrics
authors Kovalevsky, AV; Zakharchuk, KV; Aguirre, MH; Xie, W; Patricio, SG; Ferreira, NM; Lopes, D; Sergiienko, SA; Constantinescu, G; Mikhalev, SM; Weidenkaff, A; Frade, JR
nationality International
journal JOURNAL OF MATERIALS CHEMISTRY A
keywords TRANSPORT-PROPERTIES; DEFECT CHEMISTRY; ELECTRONIC TRANSPORT; ELECTRICAL-TRANSPORT; DOPED SRTIO3; POWER FACTOR; PERFORMANCE; OXIDE; TEMPERATURE; GENERATORS
abstract The development of thermoelectrics for high-temperature applications imposes several essential requirements on the material properties. In some energy-conversion scenarios, the cost and thermal stability requirements may dominate over efficiency issues, making abundant, high-temperature-stable and low-toxic oxides attractive alternative thermoelectric materials. As compared to "traditional" thermoelectrics, oxides possess unique redox flexibility and defect chemistry, which can be precisely tuned by external temperature and oxygen partial pressure conditions. This work aims to demonstrate how, by redox-sensitive substitutions, the thermoelectric properties of oxides can be tuned and enhanced. The proposed strategy is exemplified by considering molybdenum-containing strontium titanate within nominally single-substituted and nanocomposite concepts. The involved materials design allows us to proceed from an in-depth understanding of the redox-promoted effects to the demonstration of the enhanced thermoelectric performance attained by redox engineering. Synergistic enhancement of the Seebeck coefficient and suppression of the thermal conductivity due to combined carrier filtering effects and efficient phonon scattering at redox-induced interfaces provided up to 25% increase in the thermoelectric performance. The results demonstrate extraordinary flexibility of the perovskite lattice towards retaining a rich combination of the molybdenum redox states and shifting their ratio by tuning the A-site stoichiometry, and the prospects for developing new materials combining thermoelectric and (electro)catalytic functionalities.
publisher ROYAL SOC CHEMISTRY
issn 2050-7488
year published 2020
volume 8
issue 15
beginning page 7317
ending page 7330
digital object identifier (doi) 10.1039/c9ta13824b
web of science category Chemistry, Physical; Energy & Fuels; Materials Science, Multidisciplinary
subject category Chemistry; Energy & Fuels; Materials Science
unique article identifier WOS:000526936600029
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journal analysis (jcr 2019):
journal impact factor 11.301
5 year journal impact factor 10.694
category normalized journal impact factor percentile 91.814
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