Fabrication and electrochemical characterization of tape cast BaCe0.5Zr0.3Y0.16Zn0.04O3 − δ electrode/electrolyte structures

A Ni-BCZYZ electrode has been investigated in a Ni-BCZYZ|BCZYZ|Ni-BCZYZ symmetrical cell. The cell was fabricated by co-firing tape cast electrolyte and electrode framework layers and then impregnating the electrode structure with Ni(NO3)2 solution. Scanning electron microscopy of a fracture cross-section of the cell before impregnation reveals the dense, crack-free microstructure of the BCZYZ electrolyte layer with thickness of ~ 220 µm, whilst the porous layer with thickness of 100 µm shows a uniform framework with ~ 57% porosity. The distribution of 50 vol.% Ni in the BCZYZ porous structure was observed by EDS. AC-impedance spectroscopy measurements of the symmetrical cell were carried out in humidified and non-humidified 5%H2/Ar over a temperature range of 400–700 °C. The results indicate that the performance of the cell in humidified 5%H2/Ar was better than in non-humidified, especially in the high temperature range (550–700 °C). At 700 °C, the ohmic resistance of the cell about 2.8 Ω cm2 and a small polarization resistance of 0.30 Ω cm2 was obtained in humidified 5% H2/Ar.