Fabrication and electrochemical characterization of tape cast BaCe_0.5Zr_0.3Y_0.16Zn_0.04O_3-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 similar to 220 pm, whilst the porous layer with thickness of 100 mu m shows a uniform framework with similar to 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%H-2/Ar over a temperature range of 400-700 degrees 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 degrees C). At 700 degrees C, the ohmic resistance of the cell about 2.8 Omega cm(2) and a small polarization resistance of 0.30 Omega cm(2) was obtained in humidified 5% H-2/Ar. (C) 2009 Elsevier BM. All rights reserved.