Characterisation of double-sided graphene microporous layers for improved polymer electrolyte membrane fuel cell performance

This study experimentally evaluates the effects of double-sided microporous layer coated gas diffusion layers, comparing conventional Vulcan black with graphene-based microporous layers. Key properties and fuel cell performance were analysed. The results showed that adding graphene improved the in-plane electrical conductivity and increased the gas permeability compared to Vulcan black. Vulcan black microporous layers promoted a more favourable pore size distribution compared to graphene, featuring significant micropores and mesopores in both single and double-sided coatings, while pure graphene produced fewer micropores and mesopores. Contact angle measurements were consistent across all coatings, indicating that wettability depends more on the polytetrafluoroethylene content than on the carbon type. In-situ fuel cell testing demonstrated that a double-sided layer with Vulcan black facing the catalyst layer and graphene facing the bipolar plate performed best under higher humidity conditions by efficiently expelling excess water through the graphene cracks. Conversely, single-sided Vulcan black coatings performed better in low humidity, as their micropore content retained water effectively for membrane humidification.