MEA Design for Improved Cathode Durability under Startup Shutdown Automotive Conditions

Abstract

A novel MEA design solution - an "intelligent switch" to provide protection of the cathode catalyst layer from degradation caused by startup/shutdown events is proposed (1). This unique approach adapts gas sensor-type materials (2) that exhibit several orders of magnitude change in resistance depending on its gas environment (1) in PEM fuel cell anodes. The high resistance of the new layer in air environments prevents corrosion loop currents. In hydrogen environments, the layer becomes conductive and fuel cell performance is minimally hindered. In-situ fuel cell test results demonstrate a successful reduction in cathode peak potentials during startup events leading to reduced performance degradation in startup/shutdown stress tests. This strategy of preventing corrosion loop currents is compatible with various catalyst types and with different catalyst loadings. The approach enables MEA design to minimize air/air start/stop degradation and provides a pathway for the use of alternative catalyst options.