Analytical solutions for impedance of the cathode catalyst layer in PEM fuel cell: Layer parameters from impedance spectrum without fitting

A simple physical model for impedance of the cathode catalyst layer (CCL) in PEM fuel cell is solved analytically in the Tafel regime for small, but non-vanishing cell current densities (between 10 and 100 mA cm−2). Analytical results make it possible to obtain the Tafel slope, the double layer capacitance and the CCL proton conductivity from a single impedance spectrum without fitting. The method is illustrated with the experimental spectrum taken from literature.