Effect of carbon fiber length and graphene on carbon-polymer composite bipolar plate for PEMFC

Carbon-polymer composite bipolar plate is developed using novolac phenol formaldehyde resin as the polymer matrix and natural graphite, carbon black, carbon fiber, and graphene as conductive reinforcements by compression molding technique. The developed bipolar plates are characterized using electrical conductivity, flexural strength, deflection at mid-span, interfacial electrical contact resistance, and corrosion current density in simulated polymer electrolyte membrane fuel cell environment (1 M H2SO4 + 2 ppm HF at 80 A degrees C with hydrogen and oxygen purging). The effect of carbon fiber length and graphene content is studied with an overall aim to achieve the desired properties as per the stringent target properties chosen out of US-DOE and Plug Power Inc. The optimized composition of the bipolar plate is tested in a single cell polymer electrolyte membrane fuel cell set up. The optimum carbon fiber length and graphene content are found to be 1 mm and 1.5 %, respectively. The anodic and cathodic corrosion current densities are within the stringent target. Moreover, the incorporation of graphene improved the fuel cell performance significantly (13 %).