authors |
Natoli, A; Arias-Serrano, BI; Rodriguez-Castellon, E; Zurawska, A; Frade, JR; Yaremchenko, AA |
nationality |
International |
journal |
MATERIALS |
author keywords |
solid oxide fuel cell; solid oxide electrolysis cell; zirconia; manganese oxide; ionic conductivity; thermochemical expansion; oxygen nonstoichiometry; mixed conductor; buffer layer |
abstract |
Manganese-substituted 5 mol.% yttria-stabilized zirconia (5YSZ) was explored as a prospective material for protective interlayers between electrolyte and oxygen electrodes in reversible solid oxide fuel/electrolysis cells. [(ZrO2)(0.95)(Y2O3)(0.05)](1-x)[MnOy](x) (x = 0.05, 0.10 and 0.15) ceramics with cubic fluorite structure were sintered in air at 1600 degrees C. The characterization included X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetry and dilatometry in controlled atmospheres, electrical conductivity measurements, and determination of oxygen-ion transference numbers by the electromotive force (EMF) technique. Mn-substituted 5YSZ solid solutions exhibit variable oxygen nonstoichiometry with manganese cations in a mixed 2+/3+ oxidation state under oxidizing conditions. Substitution by manganese gradually increases the extent of oxygen content variation on thermal/redox cycling, chemical contribution to thermal expansion and dimensional changes on reduction. It also deteriorates oxygen-ionic conductivity and improves p-type electronic conductivity under oxidizing conditions, leading to a gradual transformation from predominantly ionic to prevailing electronic transport with increasing x. Mn2+/3+-> Mn2+ transformation under reducing atmospheres is accompanied by the suppression of electronic transport and an increase in ionic conductivity. All Mn-substituted 5YSZ ceramics are solid electrolytes under reducing conditions. Prolonged treatments in reducing atmospheres, however, promote microstructural changes at the surface of bulk ceramics and Mn exsolution. Mn-substituted 5YSZ with 0.05 <= x < 0.10 is considered the most suitable for the interlayer application, due to the best combination of relevant factors, including oxygen content variations, levels of ionic/electronic conductivity and thermochemical expansion. |
publisher |
MDPI |
isbn |
1996-1944 |
year published |
2021 |
volume |
14 |
issue |
3 |
digital object identifier (doi) |
10.3390/ma14030641 |
web of science category |
23 |
subject category |
Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter |
unique article identifier |
WOS:000615384700001
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ciceco authors
impact metrics
journal analysis (jcr 2019):
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journal impact factor |
3.057 |
5 year journal impact factor |
3.424 |
category normalized journal impact factor percentile |
58.121 |
dimensions (citation analysis):
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altmetrics (social interaction):
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