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

The fabrication, the characterization and the electrochemical performance of a solid electrolyte film of Y-doped CaZrO3 deposited on a porous SrTi0.8Fe0.2O3-delta substrate are studied in the present work. A dense 6-mu m-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 degrees 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 E-m/E-N between the measured OCV value (E-m) and the theoretical EMF value (E-N), 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. (C) 2016 Elsevier Ltd. All rights reserved.