Abstract
The current interest in solid oxide fuel cells (SOFC) technology lies mainly in its high power generation/conversion efficiency and its low or zero emissions. Their application in stationary power generation systems indicate their maturity to date. However, the stability and performance of the cells or stacks could be affected due to the adverse conditions to which they are exposed. One of the most concerning conditions for Ni-based anode-supported cells (ASC) is when the stack is subjected to unplanned reduction-oxidation (Redox) cycles, which can lead to irreversible damage to the cell. During a Redox cycle, the anode undergoes changes in its volume, due to the oxidation of nickel (Ni) to nickel oxide (NiO), which causes microstructural damages to the anode itself or to the electrolyte or to both. Previous study has shown that the cell performance decreased after redox cycling above 600 °C, mainly based on voltage-current curve or electrochemical impedance measurements. However, there is little information on the application of acoustic emission (AE) techniques in the study of redox cycling. Therefore, the purpose of this work is to investigate the redox process and stability of a SOFC stack through the application of the AE monitoring. The research will include the analysis of the AE signals, the AE cumulative energy as well as an analysis in the frequency domain. This is expected to contribute to the understanding of the redox process inside stack and failure modes of the cell.