Surface conductivity and stability of metallic bipolar plate materials for polymer electrolyte fuel cells

Different types of commercial stainless steels, Ni-based alloys and nitride-coated steels were evaluated as metallic bipolar plate in terms of interfacial contact resistance (ICR) and corrosion resistance in conditions typical of PEFC anode and cathode environments. Results show that stainless steel have a high ICR and undergo corrosion in both anode and cathode. Moreover, although Ni-based alloys showed an ICR comparable with graphite, their behaviour was not satisfactory in corrosive acidic medium. Only nitride-coated stainless steel demonstrated to have low ICR and very good corrosion resistance.