Kinetic studies of cathode degradation as caused by ice formation in MEAs

This work investigated the impact of F/T- (Freeze/Thaw) and ICV- (Isothermal Constant Voltage) cycling on the kinetic and mass transport performance loss for a PEM (proton exchange membrane) fuel cell. The loss of electrochemically active surface area (ECSA) of the cathode electrode increased with an increasing amount for F/T and ICV cycles. Kinetic performance loss and mass transport loss were only observed for the wet conditioning point. For the dry and medium conditioning points, only kinetic loss was measured. The observed trend indicates that an increased amount of residual water promotes the degradation process. During ICV-cycling, kinetic and mass transport losses were observed for all three amounts of residual water. In comparison to the F/T results, the ICV results showed the opposite trend; the higher the amount of residual water, the lower the performance loss. Finally, it was demonstrated that only F/T-cycling leads to kinetic degradation and that ICV-cycling has a significant impact on mass transport.