Detecting cathode corrosion in polymer electrolyte membrane fuel cells in dead-ended anode mode via alternating current impedance

In this work, an in-operando alternating current (AC) impedance-based method is developed to detect cathode corrosion in a polymer electrolyte membrane (PEM) fuel cell operating in dead-ended anode (DEA) mode. Polarization resistances are measured over a 2.0 s sampling time with this method, exhibiting a 10 times higher temporal resolution than conventional electrochemical impedance spectroscopy methods. The performance characteristics of a PEM fuel cell in DEA mode are investigated with both a pristine membrane electrode assembly (MEA) and a corroded MEA, and the sudden rise in the cathode polarization resistance accompanied by a uniform anode polarization resistance is identified as a new indicator for a corroded cathode. The accumulation of nitrogen in the corroded cathode leads to a rise in cathode polarization resistance. This elevated cathode polarization resistance leads to a dehydrated catalyst-coated membrane (CCM) evident through a reduction of the liquid water saturation at the CCM—microporous layer interface (observed using synchrotron X-ray radiography).