Physical modelling of cathode impedance in low temperature fuel cells

Low temperature Polymer Electrolyte Membrane (PEM) fuel cells are a promising energy source for stationary and automotive applications, mainly due to high efficiency and low emissions. However the widely use of this technology is still hindered by some technological issues, among which severe cathode flooding and degradation. The most common technique to monitor system internal losses during real operation is the Electrochemical Impedance Spectroscopy (EIS). Despite the potentiality of this in-situ measurement technique, the interpretation of impedance data is still object of discussion in the literature and physical modelling becomes crucial to analyze experiments. In this work, the development of a physically based model of cathode impedance is described and validated with respect to Direct Methanol Fuel Cell (DMFC) technology. The presented approach will be also applied to simulate cathode behavior in hydrogen fed PEM.