Influence of carbon deposition on the current distribution in an anode-supported planar solid oxide fuel cell in-situ assessed by segmented electrodes

For solid oxide fuel cells (SOFCs), durability to carbon deposition is a common problem to use hydrocarbon fuels from the city gas and the biogas. Identification of degradation factors and locations leads to development of diagnosis method and optimized operation control for prevention of failure and accident. Electrochemical data by the degradation give useful parameters for health diagnosis. In this study, we are aiming to understand spatial degradation, so that we prepared an anode-supported planar cell in which the cathode layer was segmented to three parts. We fed dry methane gas to the anode as accelerated aging tests and measured the current distribution directly among the upstream, midstream and downstream parts along the anode flow channels. Electrochemical impedance spectroscopy analysis was carried out in each segment as well. Upstream part of the cell exhibited larger overpotentials with more enhanced carbon deposition than the other parts with the dry methane fuel.