Proton exchange membrane fuel cells (PEMFC) are a viable means to meet global energy demand, reduce dependence on fossil fuels, and mitigate carbon dioxide emissions. Despite recent progress in their development, water saturation remains a challenge to current PEMFC design and efficiency. The addition of a microporous layer improves fuel cell performance largely from the reduction of water accumulation and the enhancement of mass transfer capacity at high current densities. However, optimisation of the microporous layer is necessary to improve its capability to manage liquid water and facilitate mass transfer. In this study, the viability of microporous layers produced from synthesised graphene foams was assessed.

Graphene foam was synthesised from the pyrolysis of sodium ethoxide, the resulting carbon was then subject to pyrolysis in different atmospheres in order to enhance the conductivity. The graphene foams underwent characterisation by electron microscopy and x-ray fluorescence which showed high carbon purity open foams with micron scale pores and graphene-thin walls. Microporous layers were then produced from these graphene foams, commercial graphene and from carbon black; they were then characterised ex-situ and through polarisation curves.

Ex-situ characterisation of the microporous layers was used to determine the micro-structure and physical properties, as well as its ability to repel liquid water and to conduct electron and mass transfer. Electron microscopy and mercury intrusion porosimetry enabled the analysis of morphology and microstructure, and the transport properties of the layer were determined through permeability, electrical conductivity and contact angle measurements. Polarisation curves were performed at low and high relative humidities in order to understand the capability of these microporous layers in a range of operating conditions.