Current Distribution of a PEMFC under CO Poisoning

Abstract

The current density distribution along the flow channel of a PEMFC was investigated under CO poisoning using a transparent cell modified with finely distributed current collectors. For a counter-flow configuration, significant movement of the current density peak towards the cathode exit was observed as the CO concentration in the anode gas increased, which clearly indicates that the current density is significantly reduced at the cathode inlet area and increased at the cathode exit. These results are consistent with previous experimental results that showed water droplet distributions on the cathode moved towards the cathode exit when CO at 10-100 ppm levels was introduced into the anode gas. Comparison of the experimental and calculated results revealed that movement of the current density peak under high CO was related to reduction of the exchange current density, which was caused by the significant loss of CO coverage on the anode catalyst surface.