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Effect of Nanoscale Ce0.8Gd0.2O2−δ Infiltrant and Steam Content on Ni–(Y2O3)0.08(ZrO2)0.92 Fuel Electrode Degradation during High-Temperature Electrolysis

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journal contribution
posted on 04.10.2021, 18:07 by Beom-Kyeong Park, Dalton Cox, Scott A. Barnett
Studies of Ni–yttria-stabilized zirconia (YSZ) fuel electrode degradation mechanisms in solid oxide electrolysis cells (SOECs) are complicated by the different possible Ni–YSZ microstructures and compositions, and the variations in the H2/H2O ratio encountered in an electrolysis stack. Here we describe a life testing scheme aimed at providing survey results on degradation as a function of the H2O–H2 composition, with life tests carried out at five different steam contents from 90% to 10%. A Ni–YSZ-supported symmetric cell geometry is employed both with and without infiltrated nanoscale gadolinia-doped ceria (GDC). Impedance spectroscopy is utilized to observe changes in electrochemical characteristics during the life test, and a transmission-line-based equivalent circuit is used to model the data. Post-test electrode microstructures were observed. The results suggest that the GDC infiltrant reduces the electrode polarization resistance and provides more stable electrode polarization over a range of conditions.