Expanded graphite (EG)/Ni@Melamine foam (MF)/EG sandwich-structured flexible bipolar plate with excellent electrical conductivity, mechanical properties, and gas permeability

The bipolar plate is an important component of the fuel cell. Composite graphite-based bipolar plates with adjustable properties are potential candidates to realize the high performance of the cell. However, simultaneously improving the electrical and mechanical properties of the plate is always the focus and difficulty of the research since they tend to behave with mutual inhibition. Here in this work, we report a laminating strategy to prepare composite bipolar plates with the (EG)/Ni@Melamine foam (MF)/EG sandwiched structure. The highly porous MF sponge provides enough space for epoxy immersion and the Nickel plating improves the electrical conductivity. Both the electrical conductivity (320 S/cm) and the flexural strength (56 MPa) are improved compared to the original EG plate. The enriched resin amount in the intermedium layer also ensures lower gas permeability (2.16 × 10−9 cm3cm−2s−1). In addition, owing to the residual resin on the surface of the developed plate, there is a smaller, indicating better wettability. Further practical performance tests proved that the developed plate has favorable performance under actual working conditions compared to commercialized carbon graphite plate.