Simultaneous electrical and mechanical properties improvement for composite expanded graphite bipolar plate by incorporating surface-activated carbon black paving on the carbonized melamine foam skeleton

Abstract

The bipolar plate is the critical component that directly impacts the output performance and lifespan of the fuel cell. Composite graphite-based bipolar plates, which can be tailored to exhibit desired properties, are promising candidates for high-performance fuel cells. However, the simultaneous optimization of their electrical and mechanical properties has been a major challenge in the field. This study introduces a foam skeleton made of carbonized melamine foam (CMF) into the graphite bipolar plate to create ample space for subsequent resin impregnation. Carbon black (CB) is added as a filler to form complete conductive paths, which is modified using low-temperature plasma to allow it to be more uniformly adsorbed in the skeleton. The microstructure design of the composite bipolar plate ensures excellent mechanical properties and significantly enhances its electrical conductivity. Moreover, it effectively eliminates the impact of carbon black on the surface roughness of the composite plate. This design also provides superior water management and reduces gas permeability. Practical application tests demonstrate that the developed composite plate exhibits better corrosion resistance and electrochemical stability than metal bipolar plates. Compared to carbonized bipolar plates, it displays better impact resistance and stability.