Functional properties and electrochemical performance of Ca-doped Sr2-xCaxFe1.5Mo0.5O6-δ as anode for solid oxide fuel cells
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Performance of Ca-doped strontium ferrite-molybdate Sr2-xCaxFe1.5Mo0.5O6-δ (x = 0, 0.05, 0.15, 0.3, 0.5) has been studied under reducing conditions. Thermogravimetry (TG) analysis in 5% H2/Ar and DSC measurements in high-purity argon demonstrated that the compositions are highly stable and there are no phase transitions. The best electrochemical and electrical performances of about 0.12 Ω cm2 and 33 S/cm at 800 °C in wet hydrogen, respectively, were obtained for the Sr1.85Ca0.15Fe1.5Mo0.5O6-δ anode. The EIS spectra were analyzed by means of distribution relaxation times and non-linear least squares methods, which made it possible to determine the behavior of the rate-limiting steps of hydrogen oxidation. Solid oxide fuel cells (SOFC) of planar design with the 1.5 mm LaGaO3-based supporting electrolyte, with the Sr1.85Ca0.15Fe1.5Mo0.5O6-δ symmetrical electrodes and with the Sr2-xCaxFe1.5Mo0.5O6-δ (x = 0.15 and 0.3) anode and the 70 wt% Pr0.9Y0.1BaCo2O6–δ + 30 wt% SDC cathode have been studied. The obtained results demonstrated a low anode overvoltage, which was about 0.12 V at 1 A/cm2 and 800 °C in wet hydrogen. The maximum power density of SOFC with the Sr1.85Ca0.15Fe1.5Mo0.5O6-δ anode and cobaltite cathode was about 0.18 W/cm2 at 800 °С under air/wet hydrogen conditions. The obtained results elucidate that Sr1.85Ca0.15Fe1.5Mo0.5O6-δ is a promising anode for solid oxide fuel cells.
KeywordsCa-doped Sr2-xCaxFe1.5Mo0.5O6-δ Distribution relaxation times Anode Area-specific resistance EIS Symmetrical SOFC
This work was partly carried out using facilities of the shared access center ‘Composition of Compounds’ IHTE, UB RAS. The authors would like to thank V.A. Eremin, A.S. Farlenkov, and T.A. Dem’yanenko for the assistance in the study.
The investigation of new anode materials was financially supported by the Russian Science Foundation (project no. 17-79-10207). Synthesis of solid solutions was carried out in accordance with the plans of the Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences (research, development and technological work АААА-А16-116122810216-3). The research was partially supported by the Government of the Russian Federation, agreement No. 02.A03.21.0006 (Act 211).
- 30.Tikhonov AN, Arsenin VY (1977) Solution of ill-posed problems. Winston & Sons, WashingtonGoogle Scholar