High performance polyvinylidene fluoride/graphite/multi-walled carbon nanotubes composite bipolar plate for PEMFC with segregated conductive networks

Composite bipolar plates (BPs) are preferred to graphite BPs and metal BPs, in proton exchange membrane fuel cells (PEMFC), due to their pronounced advantages. However, facile and high-efficiency fabrication of high performance composite BPs, remains a challenge. In this study, high performance polyvinylidene fluoride (PVDF)/graphite/multi-walled carbon nanotubes (MWCNTs) composite BPs with segregated conductive network are prepared by structural design and compression molding. Due to the “brick-mud” structure formed in composite BPs by structural manipulation, its conductivity of low filler content is greatly improved. In addition, segregated synergistic conductive networks are observed in composite BPs after adding MWCNTs. The composite BP (5 wt% MWCNTs and 35 wt% graphite) exhibited electrical conductivity of 161.57 S/cm and area specific resistances of 7.5 mΩ cm2. Moreover, the composite BPs have good flexural strength, excellent hydrophobicity and corrosion resistance. In summary, our work provides a simple and feasible strategy for manufacturing high performance composite BPs with low fillers. In the composite bipolar plate, Graphite and MWCNTs are selectively distributed on the interface of PVDF, forming a segregated synergistic conductive network to provide excellent electrical conductivity. [Display omitted] •Bipolar plates with segregated conductive network are developed.•Performance of bipolar plates with low filler content are greatly improved.•Composite BPs exhibits excellent in-plane conductivity and ASR performance.•The bipolar plate has good corrosion resistance and hydrophobicity.