Electrochemical characteristics of fluorine-doped tin oxide film coated on stainless steel bipolar plates

Abstract

In order to improve the interfacial contact resistance (ICR) and corrosion resistance of STS316 bipolar plates of PEMFCs, after surface pretreatment at mild plasma condition, the fluorine-doped tin oxides (FTO) thin films were deposited by electron cyclotron resonance-metal organic chemical vapor deposition. The mild plasma pre-treatment of the bipolar plate substrate before its coating with the FTO film has rendered a higher efficiency to the pertinent fuel cell, which can be attributed to a smooth charge transfer at the interface of the plate and the film due the removal of fine impurities on the substrate that could not be done just by washing. The deposition of FTO as a protect layer of fuel cell electrode after mild plasma pre-treatment improved the electrochemical stability. In our experimental range, with the increases in microwave power up to 1000W, both of the corrosion resistance and ICR significantly decreased, however, those values sharply increased above 1100W due to the crack and unstable film formation with the void space. Selecting the optimized value of the microwave power appeared to be the critical process step on the formation of the corrosion-protective layer for bipolar plates. (C) 2015 Elsevier B.V. All rights reserved.