Superhydrophobic Cobalt–Graphene Composite for the Corrosion Protection of Copper Bipolar Plates in Proton Exchange Membrane Fuel Cells

Abstract

Superhydrophobic cobalt and cobalt–graphene films were fabricated on copper bipolar plates (BPPs) using potentiostatic electrodeposition to improve their corrosion resistance and surface conductivity. A scanning electron microscope (SEM) was used to study the surface morphology of the prepared superhydrophobic films. The results show that the cobalt film modified by stearic acid (Co-SA) and cobalt–graphene composite modified by stearic acid (Co–G-SA) exhibit micro–nano structures. The results of the Fourier transforming infrared (FTIR) spectrophotometer confirm that the copper substrate was coated by Co-SA and Co–G-SA films. The wettability results of the prepared superhydrophobic films demonstrate that the films display superhydrophobicity, where the fabricated Co-SA and Co–G-SA films have contact angles (CAs) of 159 deg and 165 deg, respectively. Chemical stability, mechanical abrasion resistance, surface conductivity, and corrosion resistance in a simulated proton exchange membrane fuel cells (PEMFCs) environment are significantly higher for copper coated by Co–G-SA film. Because the copper coated with Co–G-SA has a low interfacial contact resistance (ICR) value and a high corrosion resistance, it is thought to be a good choice for PEMFC bipolar plates.