Unraveling the cohesive and interfacial adhesive strengths of electrodes for automotive fuel cells

Abstract

Despite the pressing need to develop highly durable electrodes for electric vehicles powered by polymer electrolyte membrane fuel cells (PEMFCs), evaluating the mechanical robustness of the electrodes in membrane electrode assemblies (MEAs) has proven challenging because the electrodes are intrinsically porous and brittle. Herein, we propose a novel technique for effectively quantifying the mechanical robustness of the electrodes using a surface and interfacial cutting analysis system (SAICAS). The SAICAS enables the separate quantification of cohesion and adhesion of PEMFC electrodes. We find that the adhesion at the interface is higher than the cohesion in the bulk owing to a larger intermolecular diffusion at the interface than in the bulk. Also, the SAICAS could reliably quantify the cohesion and adhesion of PEMFC electrodes having different ionomer contents and assembly temperatures. Our findings are intriguing and will be useful for the efficient and effective design and development of robust electrodes and MEAs.