Electropolymerization of camphorsulfonic acid doped conductive polypyrrole anti-corrosive coating for 304SS bipolar plates

• Published in: Applied surface science Vol. 426; pp. 87 - 98
• Main Authors: Jiang, Li, Syed, Junaid Ali, Gao, Yangzhi, Zhang, Qiuxiang, Zhao, Junfeng, Lu, Hongbin, Meng, Xiangkang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31.12.2017
• Subjects: Anti-corrosive; Bipolar plates; Camphorsulfonic acid; Conductivity; Polypyrrole; Conductivity; Anti-corrosive; Bipolar plates; Camphorsulfonic acid; Polypyrrole
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.07.077

[Display omitted] •The anti-corrosive performance of large spatial structure molecular group CSA doped PPY coating was compared with the small acid doped PPY and PPY/PPY coatings.•CSA doped PPY coating sustain the barrier effect and anodic protection during long-term immersion in the simulated PEMFC working environment.•CSA dopants enhanced the conductivity of PPY coating and the coated 304SS has low interfacial contact resistance.•Mechanism involved in durable anti-corrosive performance of PPY-CSA coating was envisaged. Conductive polymer coating doped with large molecular organic acid is an alternative method used to protect stainless steel (SS) bipolar plates in proton exchange membrane fuel cells (PEMFCs). However, it is difficult to select the proper doping acid, which improves the corrosion resistance of the coating without affecting its conductivity. In this study, large spatial molecular group camphorsulfonic acid (CSA) doped polypyrrole (PPY) conductive coating was prepared by galvanostatic electropolymerization on 304SS. The electrochemical properties of the coating were evaluated in 0.1M H2SO4 solution in order to simulate the PEMFC service environment. The results indicate that the coating increased the corrosion potential and shifted Ecorr towards more positive value, particularly the jcorr value of PPY-CSA coated 304SS was dropped from 97.3 to 0.00187μAcm−2. The long-term immersion tests (660h) show that the PPY-CSA coating exhibits better corrosion resistance in comparison with the small acid (SO42−) doped PPY-SO42− or PPY/PPY-SO42− coatings. Moreover, the PPY-CSA coating presents low contact resistance and maintains strong corrosion resistance during the prolonged exposure time due to barrier effect and anodic protection.