An ePTFE-reinforced membrane electrode assembly based on a wet-contact interface design strategy for high-performance proton exchange membrane fuel cells

The interfacial bonding between a proton exchange membrane (PEM) and catalyst layers (CLs) is a critical factor that dominates the power performance and durability of the membrane electrode assembly (MEA) in a proton exchange membrane fuel cell and therefore must be designed with considerable attention. On this basis, we present a novel MEA preparation approach by combining a wet-contact interface design strategy and expanded polytetrafluoroethylene (ePTFE) reinforcing technology to optimize the PEM/CL interfacial combination and durability of MEAs simultaneously. With a tight and robust three-dimensional PEM/CL interface, the MEAs based on the wet-contact process exhibit significantly reduced interfacial resistance and charge-transfer resistance and improved electrochemical surface area, resulting in superior power performance compared with conventional MEAs. Simultaneously, intercalating ePTFE reinforcement skeletons into the PFSA membrane obviously reduces the hydrogen crossover of the novel MEAs. Furthermore, due to the tighter PEM/CL interfacial bonding and the support of the rigid electrodes, the novel ePTFE-reinforced MEA shows less mechanical degradation than a conventional MEA based on the catalyst coated membrane method (with a Gore membrane) after a wet/dry cycle test. This is reflected by the lower increase in hydrogen crossover current, interfacial resistance, and charge-transfer resistance, as well as less power performance attenuation.