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

摘要

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.