Performance Degradation of Polymer Electrolyte Membrane Fuel Cell through Fuel Starvation Induced by Anode Flooding

Polymer electrolyte membrane fuel cell (PEMFC) stack in a fuel cell vehicle can be exposed to the flooding conditions induced by direct flow of condensed water into the electrodes through the cooled gas lines during winter. Therefore, the anode flooding was intentionally and repeatedly caused by introduction of the condensed water through the anode gas line during long-term operation, which resulted in considerable performance degradation of PEMFC. After the long-term durability test, the anode thickness was decreased, and the ratio of Pt to carbon in the anode was increased. In addition, the simulated and repeated fuel starvation situation in half-cell made the carbon surface of Pt/C catalyst severely oxidized due to induced high potential (> 1.5 V_RHE). The cyclic voltammogram (CV) of the anode in the single cell after the long-term test under the anode flooding condition indicated similar feature of oxidized carbon surface like the CV in the half-cell. Therefore, it was concluded that the repeated fuel starvation by the anode flooding generated the severe carbon corrosion in the anode since the electrode potential locally rose up higher than 1.0 V_RHE.