Experiments with Button-Type Solid Oxide Fuel Cells Using Electrochemical Impedance Spectroscopy to Detect Carbon Formation

Abstract

Carbon deposition is one of the operational problems in hydrocarbon fueled solid oxide fuel cells (SOFCs). Using electrochemical impedance spectroscopy (EIS), experiments are performed to detect carbon formation on button-type cermet Ni-YSZ/YSZ/LSM SOFCs. A mass spectrometer (MS) is used to monitor the outlet gas composition, and the distribution of relaxation times (DRT) is computed to analyse the measured impedance. This work presents preliminary results obtained for H2-CH4 mixtures at OCV and 800oC, showing an increase in the mid-frequency range (10-3 and 10-2 s) for methane concentrations exceeding 10 vol%.