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The oxygen surface kinetics of Sr2Fe1.5Mo0.5O6−δ was determined using the 16O2/18O2 isotope exchange method with gas phase analysis at 600-800 °C. The heterogeneous exchange rates (rH) and the oxygen diffusion coefficients (D) were calculated by processing the concentration dependences of the 18O fraction using Ezin's model. The rates of oxygen dissociative adsorption (ra) and incorporation (ri) were calculated based on a model using the three exchange type rates. It has been established that the rates ra and ri were comparable in this temperature range. Assumptions were made about the effect of the chemical composition of the surface on the rate of oxygen adsorption. It was found that the oxygen exchange coefficient (k) of Sr2Fe1.5Mo0.5O6−δ is comparable to that of La0.6Sr0.4MnO3±δ oxide. High values of the oxygen diffusion coefficient were found for Sr2Fe1.5Mo0.5O6−δ. The values were comparable to those of the double cobaltite praseodymium-barium and exceed by more than an order those of lanthanum‐strontium manganite. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). ; Russian Foundation for Basic Research, RFBR: 00161 ; Government Council on Grants, Russian Federation ; The study was partly financially supported by the Russian Foundation for Basic Research (17-08-00161) and the Russian Federation Government, agreement 02.A03.21.0006 (no. 211).

The paper presents the results of an investigation into thin single- and triple-layer ZrO2-Sc2O3-based electrolytes prepared using the tape-casting technique in combination with promising electrodes based on La2NiO4+δ and Ni-Ce0.8Sm0.2O2-δ materials. It is shown that pressing and joint sintering of single electrolyte layers allows multilayer structures to be obtained that are free of defects at the layer interface. Electrical conductivity measurements of a triple-layer electrolyte carried out in longitudinal and transverse directions with both direct and alternating current showed resistance of the interface between the layers on the total resistance of the electrolyte to be minimal. Long-term tests have shown that the greatest degradation in resistance over time occurs in the case of an electrolyte with a tetragonal structure. Symmetrical electrochemical cells with electrodes fabricated using a screen-printing method were examined by means of electrochemical impedance spectroscopy. The polarization resistance of the electrodes was 0.45 and 0.16 Ohm∙cm2 at 800 °C for the fuel and oxygen electrodes, respectively. The distribution of relaxation times method was applied for impedance data analysis. During tests of a single solid oxide fuel cell comprising a supporting triple-layer electrolyte having a thickness of 300 microns, a power density of about 160 mW/cm2 at 850 °C was obtained using wet hydrogen as fuel and air as an oxidizing gas. © 2020 by the authors. ; Russian Foundation for Basic Research, RFBR: 17‐08‐ 01227 ; Government Council on Grants, Russian Federation ; Funding: The study was partly financially supported by the Russian Foundation for Basic Research (17‐08‐ 01227), Russian Federation Government, agreement 02.A03.21.0006 (No. 211) and "InEnergy" LTD agreement of 2018.