Impedance Spectroscopy Study of the Dependence of High‐temperature Polymer Electrolyte Membrane Fuel Cell Parameters on Current

Abstract

A recent quasi–2D numerical model for low–temperature PEMFC impedance is modified and applied for the first time for fitting the experimental spectra of HT–PEMFC measured at low stoichiometries of the oxygen flow in the range of current densities from 20 to 160 mA cm−2. The double layer capacitance, the proton conductivity and the oxygen diffusivity of the cathode catalyst layer exhibit linear growth with current density, while the ORR Tafel slope and the GDL oxygen diffusivity are independent from the cell current. The physics behind these dependencies is discussed.