Alternating C- and Ti-dominated sublayers on bipolar plates achieve enhanced corrosion resistance under high potentials toward proton exchange membrane fuel cells

High cathodic transient potentials accelerate the dissolution of metal bipolar plates, and developing corrosion- resistant coatings is imperative. A multilayer coating that C and Ti alternatively dominated the sublayers is fabricated on SS316L (C/Ti/SS). Such an optimized composition and structure significantly expands transpassive potential to 1.6 V and thus offers full protection within the entire working potential range of proton exchange membrane fuel cells. After 10,000 cyclic polarizations with E peak of 1.6 V, a conductive TiO2 2 nanofilm forms on the surface and C/Ti/SS achieves a noticeable interfacial contact resistance of 9.43 m Omega center dot cm2, Omega center dot cm 2 , highlighting the remarkable commercial application of the novel coating.