Nonlinear Impedance Spectra Analysis of CO Poisoning on PEM Fuel Cell Performance

CO poisoning in PEM fuel cells was analyzed using nonlinear electrochemical impedance spectroscopy (NLEIS). In this methodology, the governing equations were solved without linearization, using numerical simulations. The response signal was subjected to fast Fourier transform to extract the magnitude and the phase at fundamental and higher harmonics. Linear adsorption model (Springer et. al. (8)) approach was employed to model CO adsorption. The effect of CO concentration in the feed stream, the input signal amplitude and dc bias on NLEIS response was examined. The results show that, compared to the response at fundamental frequency, higher harmonic response enable easier identification of CO poisoning effects.