Investigation of Concentration Overvoltage Increase in Low Pt-Loading PEFC

Based on the fact that concentration overvoltage increases for low Pt-loading MEAs from our previous study, we have investigated the mechanism of increase in concentration overvoltage in order to develop highly efficient low Pt-loading PEFCs. In this study, controlling water discharge in the cathode layer have been tried through two methods, lowering the relative humidity condition of MEA operation and using a more hydrophobic carbon support, graphitized Ketjen black. The second method has worked out even though the first method hasn't. Consequently, by changing the carbon support from Ketjen black to graphitized Ketjen black, approximately 60% reduction in concentration overvoltage has been successfully achieved under the 0.23 mgC/cm2 condition.