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

► A physical model for the cathode catalyst layer impedance is solved analytically. ► Solutions lead to simple relations between the key layer parameters and impedance. ► Tafel slope, DL capacitance and CL proton conductivity can be derived from the spectrum without fitting. ► The method is illustrated with the experimental impedance spectrum taken from literature.