CHARACTERIZATION OF CATHODE SUPPORTED THIN FILM ELECTROLYTES

摘要

The lower operating temperature limit of SOFCs is governed by the thermally activated conductance of the electrolyte as well as by the polarization resistance of the electrodes. For operating temperatures lower than 800℃, supported thin film electrolytes can be applied to reduce the ohmic losses within a single cell. In this work, cathode supported thin film electrolytes from state-of-the-art ceria and zirconia electrolyte powders were realized using mass production technologies. The conductivity of the electrolyte thin film was determined by impedance spectroscopy and the microstructure was characterized by electron microscopy methods (SEM). The conductivity of the electrolyte thin film (thickness < 10 μm) depends on grain size and porosity. The conductivity values of state-of- the-art electrolyte substrates (thickness > 150 μm) have not been achieved so far. However, the contribution of the electrolyte thin film to the area specific resistance is significantly smaller compared to the ASR of an electrolyte supported single cell.