Graphene oxide as a corrosion inhibitor for the aluminum current collector in lithium ion batteries

We report for the first time the use of graphene oxide (GO) as a protective coating to inhibit the corrosion of an aluminum current collector used in lithium ion batteries. We employed a simple, but effective spin-coating method for coating GO onto Al, which functioned as an effective Al corrosion inhibitor in LiPF6 as an electrolyte. Cyclic voltammetry, impedance, electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron microscopy studies all revealed that the GO strongly adheres to Al and effectively suppresses Al oxidation behaving as a charge transport barrier to pitting-causing PF6-. The GO-coating was not damaged, and, thus, the underlying native oxide layer remained intact under corrosive conditions. Charge–discharge tests performed with LiMn2O4 on a GO-coated Al current collector displayed a greater capacity with improved cyclability over LiMn2O4 on bare Al. Self-discharge testing also showed a less open circuit voltage decline for GO-coated Al, indicating Al corrosion protection by GO.