Analysis of proton and electron transport impedance of a PEM fuel cell in H2/N2 regime

Abstract

AbstractAnalytical expressions for impedance of proton and electron transport in the cathode catalyst layer of a PEM fuel cell operating in H/N regime are derived. In the high–frequency range, the dependence of imaginary part of impedance on is a straight line with the slope depending on the cathode catalyst layer (CCL) proton and electron conductivity. The characteristic frequencies of proton and electron transport associated with the double layer charging are close to each other (denoted below as ). The frequency in the cathodes of various type may differ by three orders of magnitude. DRT spectrum of CCL impedance in H2/N2 regime shows two peaks located at the frequencies and . The second frequency of electron transport in the CCL is about four times higher than . Analytical results can be used for simultaneous measurement of proton and electron conductivity of PEMFC cathodes using electrochemical impedance spectroscopy.