Novel Graphite Paper/Cu-Coated Magnesium as Bipolar Plates for Ultra-lightweight Proton Exchange Membrane Fuel Cells

Magnesium bipolar plates (BPPs) offer great advantage in realizing the ultra-lightweight target of proton exchange membrane fuel cells (PEMFCs). However, high corrosion tendency limits its application. To improve the corrosion resistance and surface conductivity of the Mg BPPs, a novel Graphite paper/Cu coating is proposed in this study. 24 h potentiostatic polarization results reveal that the corrosion current density of the coated specimen dropped by 4 orders of magnitude than that of bare Mg. In addition, the interfacial contact resistance (ICR) of Mg BPPs at 1.4 MPa was remarkably reduced after coating, from 597.22 mΩ cm2 to 5.49 mΩ cm2 after the polarization test, respectively, which reached the target set by the U.S. Department of Energy (DOE). The results illustrate that the Graphite paper/Cu coating exhibits excellent anti-corrosion and electrical property, which may offer a promising strategy for the coating design on Mg BPPs for ultra-lightweight PEMFCs.