Preparation and Performance Study of <scp>PEK</scp>‐C‐<scp>OH</scp>/<scp>MWCNT</scp>‐<scp>COOH</scp>/Graphite Composite Bipolar Plates for <scp>PEMFCs</scp> With Improved Interface Properties

ABSTRACT Bipolar plates are an essential part of proton exchange membrane fuel cells, and due to the specificity of their functions, various properties are required. In this study, a composite bipolar plate with a “sandwich” structure was prepared to solve the problems of graphite/resin composite bipolar plate, which is challenging in balancing the electrical conductivity and mechanical properties, and the interface is not tightly bonded. Through the bidirectional modification between graphite‐carbon/nanotubes and resin, the graphite phase and resin phase are connected by chemical bonding, which enhances the direct interfacial bonding performance, effectively broadens the conductive pathway, and improves the mechanical properties. The prepared composite bipolar plate showed a conductivity of 244.01 S/cm, a hydrophobicity angle of 121.4°, a flexural strength of 53.38 MPa, a corrosion current density of 0.76 μA/cm 2 , and a corrosion voltage density of 0.354 V. The composite bipolar plate showed good performance, and it is expected to be one of the candidates for future graphite/resin composite bipolar plate materials.