Investigation of anodized Ta/Ag coating on magnesium bipolar plate for lightweight proton exchange membrane fuel cells

High corrosion tendency is the bottleneck problem in the application of magnesium as lightweight bipolar plate for proton exchange membrane fuel cells (PEMFCs). This study proposes an innovative anodized Ta/Ag coating on Mg substrate, which is capable of significantly improving the anti-corrosion and electrical conduction abilities simultaneously. The corrosion behavior of the coating during immersion in the PEMFCs environment was investigated and compared with that in the working condition. In addition, the underlying mechanism of the corrosion behavior was discussed. [Display omitted] •Highly corrosion-resistant anodized Ta/Ag coated Mg bipolar plate is designed.•Anodized Ta/Ag coating possesses the long-term protection of Mg.•The corrosion current density drops by 5 orders of magnitude after coating.•The dissolution and formation of Ta2O5 greatly affect the performance of the film.