Optimization strategies to mitigate reactant starvation in a dead-ended hydrogen–oxygen proton exchange membrane fuel cell during cyclic loading

Abstract

Investigating the dynamic characteristics in hydrogen–oxygen proton exchange membrane fuel cells (PEMFCs) can provide valuable insights into the coupling degradation mechanism present within the fuel cell, which can help avoid reactant starvation and voltage decline. In this study, a recirculation subsystem is integrated into the cathode of the PEMFC to alleviate gas starvation due to water flooding. The impact of pump speed on dynamic loading is also examined. Furthermore, obstacle devices are incorporated into the cell flow channel to enhance mass transfer. The effects of flow channel configuration under the exhaust gas recirculation mode on cell performance and dynamic characteristics are investigated as well. Our findings indicate that blockage of the gas transport channel due to accumulated liquid water is the primary issue during the loading process of PEMFCs. The cathode recirculation pumps set at 600 rpm improves cell performance by 30.6% compared to the dead-ended mode at 1000 mA·cm−2. However, excessively high pump speeds lead to an increase in voltage undershoot during the loading process. Exhaust gas recirculation is found to significantly alleviate gas starvation and water flooding during the cyclic loading process and the cathode recirculation is the primary mitigation strategy for improving dynamic characteristics.