EIS as a tool to determine fuel flow distribution in molten carbonate fuel cells

• Published in: Journal of the Electrochemical Society Vol. 150; no. 12; pp. A1693 - A1698
• Main Authors: MORITA, H, NAKANO, H, MUGIKURA, Y, IZAKI, Y, WATANABE, T, UCHIDA, I
• Format: Journal Article
• Language: English
• Published: Pennington, NJ Electrochemical Society 01.12.2003
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Performance evaluation; Electrode impedance; Pressure effect; Energetic efficiency; Electrochemical polarization; Temperature effect; Molten carbonate fuel cells; Open circuit voltage
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.1624298

Electrochemical impedance spectroscopy measurements made on bench-scale molten carbonate fuel cells have been used to obtain more information on the inside state of a cell thiki polarization measurements alone offer. In the frequency range I kHz to 10 mHz, the impedance response exhibited two semicircular arcs before and after approx. 3 Hz. An equivalent circuit model and a reactor model were employed to enhance the understanding of the nature of the low-frequency arc (3 Hz-10 mHz) in the impedance response at nearly open-circuit voltage. The size of the low-frequency arc, which was obtained by the measurements, increases as the flow rate of the gas fed into the cell decreases. The diameter of the low-frequency arc and the fuel flow rate are in inverse proportion to each other. This relation provides useful information for estimating the fuel gas distribution among the stack's cells.