Deposition and Characterization of Y-doped CaZrO3 Electrolyte Film on a Porous SrTi0.8Fe0.2O3-δ Substrate

• Y-doped CaZrO3 electrolyte film was deposited on a porous SrTi0.8Fe0.2O3-δ substrate.
• Multi-step chemical solution deposition was used for the film preparation.
• Average ionic transport number in CaZrO3-based film under pO2 gradient is 0.93–0.97.
• Polarization losses in the cell Pt/STF/CZY-film/Pt lead to poor electrochemical performance.

The fabrication, the characterization and the electrochemical performance of a solid electrolyte film of Y-doped CaZrO3 deposited on a porous SrTi0.8Fe0.2O3-δ substrate are studied in the present work. A dense 6-μm-thick film of the electrolyte is prepared by multi-step chemical solution deposition. Phase purity, concentrations of the elements and microstructure of the film are characterized by means of X-ray diffraction, energy-dispersive X-ray spectroscopy and scanning electron microscopy. The results indicate interdiffusion between the film and the substrate. For the electrochemical characterization of the electrolyte film a gas concentration cell Pt/STF/CZY-film/Pt is fabricated. Open circuit voltage (OCV), impedance spectra (EIS) and current-voltage characteristics are measured at the oxygen concentration cell in the temperature range from 500 to 600 °C. The ionic transport numbers in the electrolyte film determined from the impedance and OCV data are found to vary within 0.93–0.97 interval. This is significantly higher than the ratio Em/EN between the measured OCV value (Em) and the theoretical EMF value (EN), which determines the transport numbers in the case of non-polarizable electrodes. It is concluded that this difference is caused mainly by the high polarization resistance of the cell.

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