Understanding the functions and modifications of interfaces in membrane electrode assemblies of proton exchange membrane fuel cells

Abstract

Interfaces in membrane electrode assemblies (MEAs) refer to the contacting region between two neighboring layers, and on both the anodic and cathodic sides, there is a proton exchange membrane/catalyst layer (PEM/CL) interface, catalyst layer/microporous layer (CL/MPL) interface and microporous layer/carbon fiber paper (MPL/CFP) interface. Although these interfaces play important roles in fuel cell performance and durability, they have not been comprehensively and systematically investigated and summarized. Here, we intend to provide an understanding of the functions and modifications of interfaces for future related studies and applications. Four primary functions are proposed for interfaces in MEAs: mechanical adhesion, charge transfer, mass transport, and heat conduction. Based on the understanding of relevant research, modifications concerning different interfaces have been categorized according to their effectiveness in these functions to provide a modification toolbox that may help fuel cell developers regarding specific interfacial issues. Meanwhile, challenges and future research trends regarding interfacial modifications are proposed.