Reducing contact resistance of macro-scale separable electrical contacts with single-layer graphene coatings

Systems in applications ranging from aerospace, automotive, to power distribution are all crucially comprised of electrical connectors. Every system with removable electrical components will have electrical connectors, and likewise these systems will be susceptible to the contact losses and failure modes of these connections. Corrosion is one of the largest causes of failure for electrical connectors and costs the electrical power distribution system in the United States hundreds of millions of dollars annually. This study demonstrates the viability graphene as a protective coating for copper connectors to mitigate corrosion and improve electrical contact performance. Graphene, which is constituted of single layers of hexagonally-oriented carbon atoms, is inherently ultra-thin, chemically and thermally stable, gas impermeable (a property which can inhibit corrosion), highly electrically conductive, and made from an abundant and low-cost components, making it an ideal candidate for implementation as a protective coating on electrical contacts. In this work, single-layer graphene was deposited on copper used in commercially-available electrical connectors. In static tests the electrical contact resistance of the graphene-coated copper contact was two orders of magnitude lower than the contact resistance of the bare copper, and performed similarly to a benchmark gold/nickel coating that is a widely-used anticorrosive coating, demonstrating graphene´s protective utility.