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 mu A/cm(2) to 0.058 mu A/cm(2), meanwhile, the interfacial contact resistance (ICR) between carbon paper and coated magnesium drops from 100.6 m Omega(2) cm(2) to 27.28 m Omega(2) cm(2) 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.

Automated summary

This paper investigates the use of a hydrophobic Polytetrafluoroethylene (PTFE)/Carbon cloth/Ag multilayer coating to enhance the corrosion resistance and electrical properties of magnesium alloy bipolar plates. The multilayer coating significantly reduces the corrosion current density of bare magnesium and improves the interfacial contact resistance between carbon paper and coated magnesium. Discussing the mechanism behind the superior corrosion resistance and electrical properties of coated magnesium may pave the way for the development of novel lightweight magnesium alloy PEMFC bipolar plates.