Ionic transport in (La,Sr)CoO3-delta ceramics

authors	Tsipis, EV; Naumovich, EN; Patrakeev, MV; Yaremchenko, AA; Kovalevsky, AV; Waerenborgh, JC; Kharton, VV
nationality	International
journal	JOURNAL OF SOLID STATE ELECTROCHEMISTRY
keywords	MIXED CONDUCTIVITY; OXYGEN NONSTOICHIOMETRY; MOSSBAUER-SPECTRA; COBALTITE CATALYSTS; LA1-XSRXCOO3-DELTA; THERMODYNAMICS; PERMEATION; MECHANISMS; EXPANSION; EXCHANGE
abstract	Increasing Sr2+ concentration and the creation of A-site deficiency in La1-x-ySrxCoO3-delta (x = 0.3-0.7, y = 0-0.05) increase oxygen ionic conductivity, oxygen permeability of the dense ceramic membranes, and surface exchange limitations, in correlation with the oxygen nonstoichiometry variations. Regression analysis of the experimental data on oxygen deficiency and steady-state oxygen permeation fluxes demonstrated an important role of the defect association processes, namely, clustering of the oxygen vacancies and Co2+. The X-ray diffraction and Mossbauer spectroscopy studies of model Fe-57-doped composition, (La0.3Sr0.7Co0.99Fe0.01O3-delta)-Fe-57, confirmed that the ordering processes occur on reduction. In the case of La0.5Sr05CoO3-delta when oxygen transport limitations by bulk ionic conduction and surface exchange are comparable, the exchange limitations are located essentially at the membrane permeate-side surface. Reducing p(O-2) and temperature leads to greater surface limitations. The chemically induced lattice expansion increases with increasing both x and y in La1-x-ySrxCoO3-delta, as well as with increasing temperature. The apparent thermal expansion coefficients calculated from the dilatometric data in air vary from (16-17) x 10(-6) K-1 at 300-950 K up to (28-31) x 10(-6) K-1 at 750-1370 K.
publisher	SPRINGER
issn	1432-8488
isbn	1433-0768
year published	2021
volume	25
issue	12
beginning page	2777
ending page	2791
digital object identifier (doi)	10.1007/s10008-021-05023-8
web of science category	15
subject category	Electrochemistry
unique article identifier	WOS:000712184900002