Research progress in surface modification of metal bipolar plates for proton exchange membrane fuel cells

Bipolar plates are the core components of proton exchange membrane fuel cells (PEMFC), and their quality directly determines the output power and service life of the battery stack. Metal bipolar plates have attracted intensive attention and become the research focus of bipolar plates in PEMFC due to their excellent mechanical and electrical performances. Unfortunately, bare metal bipolar plates are prone to corrosion in PEMFC. After the corrosion of metal bipolar plates, the released metal ions could poison the catalyst, and the formed dense oxide film could increase the interface contact resistance, affecting the output power and service life of the PEMFC. Surface modification of metal bipolar plates can effectively tackle the aforementioned problems. In this review, firstly, the types, merits and disadvantages of bipolar plates are introduced. Subsequently, preparation methods, performances and the latest research progress of surface modified coatings, such as metallized coating, carbon based coating and conducting polymer coating, for metal bipolar plates are systematically summarized. Finally, the commercialization challenges of modified coatings in China and current industrialization situation at home and abroad are analyzed. Furthermore, the development direction of surface modification of metal bipolar plates is prospected from the point of view of cost and service life.