Local Transients of Flooding and Current in Channel and Land Areas of a Polymer Electrolyte Fuel Cell

Submillimeter resolved current density distribution measurements and in-plane neutron radiography were used simultaneously in voltage step experiments for the local investigation of flooding and cell performance in cathode channel and land areas of a polymer electrolyte fuel cell. Our results demonstrate that oxygen depletion leads to a strong performance loss under the ribs already before the onset of a notable liquid water accumulation. Here, the detrimental effect of liquid water accumulation on cell current is more likely associated with a loss of electrode performance rather than the result of a decreasing effective diffusivity for oxygen in the gas diffusion layer.