Low filler and highly conductive composite bipolar plates with synergistic segregated structure for enhanced proton exchange membrane fuel cell performance

Abstract

The high conductivity of bipolar plate (BP) is crucial to the performance improvement of proton exchange membrane fuel cell (PEMFC). However, the traditional composite BP usually contain about 60–80 wt% conductive fillers, which will lead to poor mechanical strength and inferior processing performance. In this work, we manufactured a low filler and highly conductive PVDF-graphite-carbon black composite bipolar plates with synergistic segregated structure by structural design strategy, which can significantly improve the performance of PEMFC. The segregated PVDF-graphite-carbon black composite BP containing only 6 wt% carbon black and 34 wt% graphite exhibits an in-plane conductivity of 177.87 S/cm and area specific resistance of 9.30 mΩ∙cm2. The conductivity of the in-plane and through-plane is 256.78 and 9704.50 times higher than that of the composite BP with random dispersion of graphite and CB, respectively. The PEMFC single cell with the composite BP exhibits a maximum power density of 646.08 mW/cm2, which is much higher than that of conventional composite BP. Besides, the composite BP exhibit excellent flexural performance, hydrophobicity and satisfactory corrosion resistance. Therefore, the composite BP with segregated conductive network is a promising candidate for PEMFC.