Method for in situ carbon deposition measurement for solid oxide fuel cells

• A method for measuring carbon deposition in SOFC anodes in situ is developed.
• Only carbon deposits that have intimate contact with nickel can be gasified.
• >99.8 mass % of carbon with residence times up to 100 h can be gasified.
• Quantification of gasified carbon shows good agreement with TGA measurements.
• The observed effect of increased steam content is in agreement with the literature.

Previous methods to measure carbon deposition in solid oxide fuel cell (SOFC) anodes do not permit simultaneous electrochemical measurements. Electrochemical measurements supplemented with carbon deposition quantities create the opportunity to further understand how carbon affects SOFC performance and electrochemical impedance spectra (EIS). In this work, a method for measuring carbon in situ, named here as the quantification of gasified carbon (QGC), was developed. TGA experiments showed that carbon with a 100 h residence time in the SOFC was >99.8% gasified. Comparison of carbon mass measurements between the TGA and QGC show good agreement. In situ measurements of carbon deposition in SOFCs at varying molar steam/carbon ratios were performed to further validate the QGC method, and suppression of carbon deposition with increasing steam concentration was observed, in agreement with previous studies. The technique can be used to investigate in situ carbon deposition and gasification behavior simultaneously with electrochemical measurements for a variety of fuels and operating conditions, such as determining conditions under which incipient carbon deposition is reversible.