Recent advances in conducting polymer coatings for metal bipolar plates in PEMFC

Metal materials such as stainless steel (SS) and titanium alloys have been considered as ideal materials for bipolar plates (BPs) in proton exchange membrane fuel cells (PEMFCs) owing to high electrical conductivity, high thermal conductivity, good mechanical strength and processability. However, metal BPs would be corroded in the acidic working condition of PEMFC. In recent years, conducting polymer coatings (CPCs) have attracted much attention in the corrosion protection of metal BPs for the good corrosion resistance and conductivity. In this paper, we systematically review the recent advances in CPCs for metal BPs based on the two categories of non-intrinsic conducting polymer (NICP) coatings and intrinsic conducting polymer (ICP) coatings. The progress of NICP coatings for metal BPs mainly focuses on the three types of conducting fillers: noble metal materials, carbon materials and transition metal compound materials, while the progress of ICP coatings for metal BPs is discussed based on the three modification strategies: doping modification, nanomaterial modification, and bilayer coatings. Furthermore, the challenges and perspectives of CPCs coatings for metal BPs are also discussed, which would help to provide guidance for the further research of CPCs for metal BPs.