Experimental analysis of spatio-temporal behavior of anodic dead-end mode operated polymer electrolyte fuel cell

During the anodic dead-end mode operation of fuel cells, the inert gases (nitrogen and water) present in the cathode side gas channel permeate to the anode side and accumulate in the anode gas channel. The inert gas accumulation in the anode decreases the fuel cell performance by impeding the access of hydrogen to the catalyst. The performance of fuel cell under potentiostatic dead-end mode operation is shown to have three distinct regions viz. time lag region, transient current region and a steady state current region. A current distribution measurement setup is used to capture the evolution of the current distribution as a function of time and space. Co- and counter-flow operations of dead-end mode confirm the propagation of inert gas from the dead-end of anode channel to the inlet of anode. Experiments with different oxidants, oxygen and air, under dead-end mode confirm that nitrogen which permeates from cathode to anode causes the performance drop of the fuel cell. For different starting current densities of 0.15 A cm−2, 0.3 A cm−2 and 0.6 A cm−2 the inert gas occupies 35%, 45% and 57%, respectively of anode channel volume at the end of 60 min of dead-end mode operation.

► Spatio-temporal propagation of inert gas in the dead-end mode of anode is experimentally captured.
► Contribution of nitrogen and oxygen to the reversible performance drop is delineated.
► Initial lag period during dead-end mode operation is dictated by the membrane.