Enhanced anticorrosion performance of PPY-graphene oxide/PPY-camphorsulfonic acid composite coating for 304SS bipolar plates in proton exchange membrane fuel cell

The enhanced corrosion resistance with sustained conductivity are the prerequisites of stainless steel bipolar plates for practical application in proton exchange membrane fuel cell. Herein, we prepare a conductive polypyrrole-graphene oxide/polypyrrole-camphorsulfonic acid bilayer composite coating (PPY-GO/PPY-CSA) on 304 stainless steel bipolar plate by electrodeposition method. The electrochemical tests are conducted in the simulated bipolar plates working environment, the potentiostatic polarization results imply that the PPY-GO/PPY-CSA composite coating offers stable corrosion resistance with low potentiostatic corrosion current density in comparison with the PPY-GO coating. The corresponding electrochemical impedance spectroscopy measurements reveal that the PPY-GO/PPY-CSA composite coating exhibits satisfactory conductivity and displays sustained anodic protection effect with superior anticorrosion performance during the 696   h of immersion. The excellent corrosion protection ability of the PPY-GO/PPY-CSA composite coating owing to its good adhesion strength, compact structure, satisfactory conductivity as well as the synergetic interaction between the two layers of the coating.