A Highly Durable Quercetin-Based Proton Exchange Membrane for Fuel Cells

Chemical degradation is one of the most serious problems that can affect the performance of a proton exchange membrane fuel cell. Reactive oxygen species generated at the cathode can result in membrane thinning along with the appearance of pinholes and cracks, all of which reduce the lifespan of the device. In the present study, quercetin was added to cast Nafion membranes as a free radical scavenger to mitigate this problem. The incorporation of only 1 wt% quercetin was found to significantly reduce chemical degradation, as reflected in improved cell performance and hydrogen crossover. A comparison between quercetin and CeO2 (a general free radical scavenger for proton exchange membrane fuel cells) showed that quercetin had superior free radical scavenging properties to CeO2. The results of this work demonstrate that oxidized quercetin (that is, the quinone form) can be reduced back to quercetin by treating the cell with hydrogen. Therefore, quercetin can provide continuing protection to a proton exchange membrane, such that the lifespan of the system is greatly enhanced.