Ion transport in dual-phase SrFe1−xТаxO3−δ (x = 0.03 − 0.10): effects of redox cycling

Autor: Vladislav V. Kharton, João C. Waerenborgh, Ekaterina V. Tsipis, Victor L. Kozhevnikov, I. A. Leonidov, Alexey A. Markov, E. V. Shalaeva, A. M. Murzakaev, Alexander P. Tyutyunnik, Mikhail V. Patrakeev
Rok vydání: 2014
Předmět:
Zdroj: Journal of Solid State Electrochemistry. 19:841-849
ISSN: 1433-0768
1432-8488
DOI: 10.1007/s10008-014-2698-2
Popis: The incorporation of tantalum cations in mixed-conducting SrFe1-xTaxO3−δ (x = 0.03 − 0.10) results in the formation of single cubic perovskite-like phases in oxidizing atmospheres while under reducing conditions phase separation is observed, accompanied with an appearance of brownmillerite-type nanodomains on the background of the perovskite-like matrix. For SrFe0.97Ta0.03O3−δ after reduction, the x-ray and electron diffraction studies combined with transmission electron microscopy evidence the formation of approximately 30 vol.% brownmillerite phase with an average domain size of 20–40 nm. The oxygen partial pressure dependencies of the total conductivity in the \( {p}_{{\mathrm{O}}_2} \) range from 10−20 to 0.5 atm at 700–950 °C show that the electron transport parameters remain virtually independent on the dopant content and domain structure. Contrary to the materials with higher dopant content, however, the ion conduction in SrFe0.97Ta0.03O3−δ tends to substantially increase on redox cycling. This behavior was attributed to the brownmillerite domain disintegration and rearrangement, induced by cyclic formation and disappearance of oxygen vacancies.
Databáze: OpenAIRE
Externí odkaz: