Characterization of the Degradation in Membrane Electrode Assemblies Through Passive Electrical Measurements

A passive technique to characterize the degradation of membrane electrode assemblies is presented; it is based on simple measurement of electrical characteristics as a function of time. This method relies on the experimental evidence that the assembly behaves like a supercapacitor with a tremendous capacity in series with a small resistance. In a first approximation, a resistor-capacitor (RC) circuit can thus be utilized to model the charging and discharging behavior. The experimental data demonstrated that a more sophisticated equivalent circuit was necessary to understand the experimental results. The most favorable set of parameters was determined, thanks to a Monte Carlo type numerical analysis. Overall, a larger sensitivity to damage detection than the well-accepted electrochemical impedance spectroscopy is demonstrated that suggests a promising future to in situ detection of failure and understanding of degradation mechanisms.