Self-sustained oscillations in the potential of a CO-poisoned PEM fuel cell: A model based on physical principles

Abstract

A dynamic 1-D model for the simulation of the oscillatory behavior in the anode potential of a PEM fuel cell under constant current conditions and the presence of CO impurities in the H2 inlet is presented. The model is built upon electrostatic, chemical kinetic and thermodynamic principles, featuring a probabilistic treatment of dipole interactions between several chemical species in the compact layer. Model predictions are validated with available experimental data in the literature. The model is able to capture the phenomenon of the oscillatory behavior. This phenomenon occurs when the CO molar fraction in the feed exceeds 8 × 10−5. A parametric sensitivity study for CO-electrooxidation and OH-adsorption kinetic rates is also performed. The CO-electrooxidation rate has a noticeable effect on the oscillation frequency, and damped oscillations are observed for a kinetic rate of 6 × 10−3 mol m−2s−1, while OH-adsorption and desorption rates have a moderate effect on system dynamics.