A novel high corrosion-resistant polytetrafluoroethylene/carbon cloth/Ag coating on magnesium alloys as bipolar plates for light-weight proton exchange membrane fuel cells.

Magnesium alloy is a promising material for light-weight bipolar plates of proton exchange membrane fuel cell (PEMFC) owing to its low density, but high susceptibility to corrosion limits the application. In this paper, a novel hydrophobic Polytetrafluoroethylene (PTFE)/Carbon cloth/Ag multilayer coating is fabricated on Mg substrate. Potentiodynamic polarization results reveal that the multilayer coating decreases the corrosion current density of bare Mg dramatically from 17.24 μA/cm2 to 0.058 μA/cm2, meanwhile, the interfacial contact resistance (ICR) between carbon paper and coated magnesium drops from 100.6 mΩ cm2 to 27.28 mΩ cm2 at 1.4 MPa. The mechanism of the superior corrosion resistance and electrical property of coated Mg is discussed, which may shed light on the development of the novel light-weight magnesium bipolar plates of PEMFC. Image 1 • Novel hydrophobic PTFE/Carbon cloth/Ag coating is developed for Mg bipolar plates. • Corrosion current density drops from 17.24 μA/cm2 to 0.058 μA/cm2 after coating. • The ICR of PTFE/Carbon cloth/Ag coated Mg is only one-third of that for bare Mg. • Superior anti-corrosion and electrical property is obtained by the novel coating. [ABSTRACT FROM AUTHOR]