Carbon fiber fabric/graphite reinforced polyphenylene sulfide composite for fuel cell bipolar plates

Bipolar plates are an important component of proton exchange membrane fuel cells, which need to have excellent electrical conductivity, gas tightness, flexural strength, and corrosion resistance. Carbon-filled resin composite bipolar plates have excellent corrosion resistance, but their electrical conductivity often falls short of the required standards. In this paper, carbon fiber fabrics are used to form a laminated structure with graphite and polyphenylene sulfide, in order to improve the electrical conductivity along with mechanical performance. It is found that the carbon fiber fabric significantly enhanced the electrical conductivity of the plates from 21.9 to 123.2 S/cm. Meanwhile, the flexural strength was also improved remarkably from 21.9 to 51.6 MPa. Both far exceed the US Department of Energy (DOE) standard. Moreover, when a graphitized carbon fiber fabric was adopted, the in-plane conductivity was further increased to 286.7S/cm, while the flexural strength decreased to 44.44 MPa, but still exceeds the DOE standard requirements. It is considered that the carbon fiber fabrics built a conductive network synergistically with graphite in the composite. This study makes a positive contribution to the development of composite bipolar plates and the advancement of their applications in the automotive field.Highlights Building conductive networks with (graphitized) carbon fiber fabrics and graphite. Balanced electrical properties and flexural strength of composite bipolar plates. Bipolar plates have excellent electrical properties and flexural strength. Bipolar plates have excellent corrosion resistance. The bipolar plate, prepared by graphitizing carbon fibers, exhibits ultra-high in-plane conductivity.