Conductive amorphous carbon-coated 316L stainless steel as bipolar plates in polymer electrolyte membrane fuel cells

• Published in: International journal of hydrogen energy 2009-08, Vol.34 (16), p.6771-6777
• Main Authors: Feng, Kai, Shen, Yao, Sun, Hailin, Liu, Dongan, An, Quanzhang, Cai, Xun, Chu, Paul K.
• Format: Article
• Language: English
• Subjects: Anodes; Anodic protection; Applied sciences; Austenitic stainless steels; Bipolar plate; Carbon film; Cathodes; Close field unbalanced magnetron sputter ion plating; Coating; Current density; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Heat resistant steels; Polymer electrolyte membrane fuel cells; Simulation; Stainless steel 316; Stainless steels
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2009.06.030

Amorphous carbon (a-C) film about 3 μm in thickness is coated on 316L stainless steel by close field unbalanced magnetron sputter ion plating (CFUBMSIP). The AFM and Raman results reveal that the a-C coating is dense and compact with a small size of graphitic crystallite and large number of disordered band. Interfacial contact resistance (ICR) results show that the surface conductivity of the bare SS316L is significantly increased by the a-C coating, with values of 8.3–5.2 mΩ cm 2 under 120–210 N/cm 2. The corrosion potential ( E corr) shifts from about −0.3 V vs SCE to about 0.2 V vs SCE in both the simulated anode and cathode environments. The passivation current density is reduced from 11.26 to 3.56 μA/cm 2 with the aid of the a-C coating in the simulated cathode environment. The a-C coated SS316L is cathodically protected in the simulated anode environment thereby exhibiting a stable and lower current density compared to the uncoated one in the simulated anode environment as demonstrated by the potentiostatic results.