A graphene-based microporous layer for proton exchange membrane fuel cells: Characterization and performance comparison

Water management is a critical issue for proton exchange membrane (PEM) fuel cells, and the use of a microporous layer (MPL) substantially improves the PEM fuel cell performance, reliability and durability through improved water management. In this study, graphene, technically a yet-to-be-developed category of material, is investigated as a potential MPL material, due to its high electrical and thermal conductivity. MPLs made of graphene (G-MPL) have been fabricated and assessed through morphological, microstructural, physical, and electrochemical characterizations and performance testing in a single scaled-up cell. Comparison is also made with MPLs made of a conventional material, Vulcan (V-MPL). The results show that the G-MPL has a unique morphology composed of horizontally packaged graphene flakes that improves water management, in-plane electrical conductivity (up to 2 times), catalyst activity, and platinum (Pt) utilization (up to 10%). The cell with the G-MPL has a better performance than the cell with the V-MPL under both fully (100% RH) and partially (40% RH) humidified conditions, with the peak power densities of 0.98 W cm−2 and 0.60 W cm−2, respectively - these peak power densities are about 7% and 43% higher than those obtained for the cell with the V-MPL at 100% and 40% RH, respectively.