Paradox phenomena of Proton Exchange Membrane Fuel Cells operating under dead-end anode mode

By using two spatially separated reference electrodes in a single cell proton-exchange membrane fuel cell (PEMFC), the individual potentials of the anode and cathode are recorded under realistic operating conditions. The PEMFC was operated under dead-end anode (DEA) mode, without any humidification, to mitigate water accumulation at the anode. Although N2 crossover from cathode to anode may play an important role in PEMFCs operating under DEA mode, our results unexpectedly show that the over-potentials of both the anode and cathode concomitantly increased or decreased at the same time. These changes in over-potential correlate to the high frequency resistance of the cell (Rhf) implying that the water content in the membrane electrode assemblies is critical. However, the subsequent H2 depletion tests suggest that water may accumulate at the interface between the surface of the catalyst and the ultrathin perfluorosulfonic acid (PFSA) ionomer film and this contradicts the above (the increase in Rhf implies the drying out of the MEAs). This study highlights the need for further research into understanding