Stainless steel as bipolar plate material for polymer electrolyte membrane fuel cells

Due to their low cost, high strength, ease of machining and shaping into thin sheets, as well as their corrosion resistance, stainless steels are considered to be good candidates for bipolar plate materials for the polymer electrolyte membrane fuel cell (PEMFC). We have tested several stainless steels in simulated PEMFC environments for application as bipolar plates. The results showed that the chromium content in the steel alloys has an important influence on the anodic behavior. The interfacial contact resistance of the carbon paper/stainless steel interface has been evaluated. Both tests show that 349™ is the best candidate for this application. When 349™ stainless steel was polarized in simulated PEMFC environments, it was found that stable passive films formed within 30 min. The interfacial contact resistance between the carbon paper and stainless steel increased due to the formation of the passive film. However, as soon as a stable passive film is formed, the interfacial contact resistance stabilized.