A simple in situ characterization technique for the onset of the chemical degradation of PEM fuel cells’ fluorinated membranes

The onset of the chemical degradation of the fluorinated PEM fuel cells’ membranes is characterized using an in situ novel technique. It is based upon measuring the pH of the water drained out from the cathode and the anode compartments using a flow pH meter connected to these outlets. It was found that the acidity of water increases significantly as the load increases if the cell operates at low temperature–low relative humidity (RH) condition after it was working at high temperature–high RH condition previously. Degradation rates were calculated from the pH measurements.