Graphene-based microporous layers for enhanced performance in PEM fuel cells

In this work, the employability of graphene nanoplatelets in the Microporous Layer (MPL) of Polymer Electrolyte Membrane Fuel Cells (PEMFCs) instead of conventional carbon black is studied. This effort is aimed at improving two critical issues that this component faces, which are the water management and the durability under harsh cell operating conditions. Both morphological and electrical properties of the MPLs produced have been assessed. Distinctive features have been identified, particularly in terms of surface aspect via SEM imaging and porosity through mercury intrusion porosimetry. Electrochemical testing has displayed impressive results for graphene nanoplatelets under low humidity conditions (80 °C and relative humidity equal to 60%), compatible with those achieved by carbon black at lower temperature (60 °C), suggesting an improved water retention in the electrolyte that maintains unaltered its ionic conductivity. In addition, a greater reliability and endurance for graphene-based samples have been detected through repetitive testing and cell flooding: little or no voltage losses have been recorded after 13 single cell testing procedures and reduced material detachment has been observed after the cell disassembly, suggesting a superior mechanical resistance by these material.