Enhanced PEMFC Cathode Kinetics at 120 {degree sign} C and Low Relative Humidity Using Heteropolyacid Additives

摘要: Operation of polymer electrolyte membrane fuel cells (PEMFCs) at elevated temperatures and low relative humidity is limited by the electrolyte’s dependence on water. Addition of heteropolyacids, specifically silicotungstic acid (STA), is shown to increase activity by nearly 35% at 118 C/40% RH. Additionally, activity for STA-containing cells is improved at 118 C/40% RH over the activity of the same cells at 78 C/100% RH. Electrochemically active areas are not affected by addition of STA, implying a mechanism other than increased wetting of the platinum catalyst, is responsible for the increased activity.