Electrochemical Noise Measurement and Analysis of Hydrogen-air PEM Fuel Cell

Abstract

The method of measurement and analysis of electrochemical noise was used to test a hydrogen-air polymer electrolyte fuel cell and its electro catalytic electrodes. The measurement was carried out during stepped electrochemical aging. After each aging step, the electrochemical noise was measured and analyzed. Besides, power characteristics of the fuel cell and its impedance spectrums were collected to characterize fuel cell at different stages of aging. These data were compared with the electrochemical noise analysis results. Experimental study of electrochemical noise of PEM fuel cell electrodes in a liquid electrolyte during artificial degradation in solutions saturated by various gases was carried out. A decrease in activity due to the degradation of the electrodes was showed to be accompanied by a decrease in the integral of noise amplitude and a significantly lower dependence of frequency exponent (and associated Hurst exponent). At the first stage of noise analysis, a baseline was subtracted from the initial signal. Various approaches for baseline determination were used, namely polynomial approximation and the method of moving average. At the next stage of noise analysis, a Fourier transform was applied. A decrease in magnitude of peaks for some characteristic frequencies was shown to correlate with the decrease in load currents in the course of fuel cell aging.