Tuesday, 15 October 2019
Grand Ballroom (The Hilton Atlanta)
Solid oxide fuel cells (SOFCs) have been of practical concern for high efficiency power generation and fuel flexibility. In the planar SOFCs, current and temperature distributions due to fuel consumption and steam generation occur from the upstream to the downstream part along the anode flow channels, causing problems such as lower efficiency and durability. Furthermore, durability to carbon deposition is a common problem with hydrocarbon fuels derived from natural gas and biogas. Identification of degradation factors and locations leads to development of diagnosis method and optimized operation control for prevention of failure and accident. In-situ electrochemical data by the degradation give useful parameters for health diagnosis of SOFCs. In this study, we aim to clarify the spatial degradation behavior using an anode-supported planar cell with a cathode layer segmented into 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 for each segment as well. For the obtained impedance spectra, curve fitting by nonlinear least squares method was carried out to separate each resistance for the analyses. Upstream part of the cell exhibited larger resistance with more enhanced carbon deposition than the other parts with the dry methane fuel.