Tracking Localized Degradation of Solid Oxide Cells Via Multi-Physics Modelling of Impedance Spectroscopy

Abstract

Multi-physics models have proven valuable tools for describing and understanding degradation of solid oxide cells (SOC). One shortcoming of the approach is the restricted validation of degradation theories with only the transient voltage or current characteristics measured globally over SOCs. Such an approach disregards the additional insights via periodically measured impedance spectra that is common practice in experimental durability tests. This work overcomes these limitations by applying a combined transient-frequency domain approach permitting the description of temporal changes and the evolution of impedance spectra. It finally leads to a framework allowing trustworthy validation of degradation mechanism represented via multi-physics models. This approach is implemented for an electrode-supported SOC operated in electrolysis mode at -1 A/cm2 aiming at a separation between the different degradation modes of the Nickel/8mol% Yttria stabilized Zirconia electrode.