Impact of Graphite on Unsaturated Polyester/graphite Composites for the Fabrication of Bipolar Plates

A bipolar plate is one of the most important components of a fuel cell with a proton exchange membrane. Due to the requirement to retain high electrical conductivity, superior mechanical qualities, and low production cost, the development of a suitable material for use as bipolar plate is crucial from a scientific and technological standpoint. Graphite based composites are a viable substitute for metal-based BPs because of their superior mechanical qualities, corrosion resistance, recyclability and cost-effective manufacturing processes. In this work, we attempted to prepare graphite-unsaturated polyester resin composites that would satisfy the technical goals set by the US DOE for 2020 while also making sure that dielectric nature and mechanical strength were well-balanced. Specifically, we tried to investigate how the filler to binder ratio affected the mechanical and dielectric characteristics. With an increase in the amount of graphite up to 5%, the composites' hardness and tensile strength climbed linearly whereas the overall elongation diminishes. The composites' flexural and compressive strengths and the total elongation for compressive and flexural strength increases upto 3% graphite and subsequently drops down as the graphite percentage increases. Composites with 1% graphite have the maximum dielectric strength, while those with 3% graphite show the lowest. Based on these findings, we suggest that a composite that contains between 1% and 3% graphite would work well as a bipolar plate.