CVD graphene coating of Cu cables for low voltage domestic and industrial wiring

Copper is commonly employed in industrial wiring applications, owing to its excellent thermal, electrical and mechanical properties. On the other hand, Cu wires are easily oxidized when exposed to air [1] and this drawback worsens their electrical performances through time. With the aim of saving production and raw material costs, nowadays research efforts are devoted to the development of effective processes and coatings to increase Cu electrical conductivity, and possibly preserve it over time [2]. Graphene grown via chemical vapor deposition (CVD) is an interesting candidate material for ultrathin coating of Cu wires thanks to its high thermal and electrical conductivity, strength and adhesion to the original morphology of the surface [3,4]. In this framework, high-quality CVD graphene was easily grown on commercial Cu wires, fulfilling the requirements for an industrial production line, i.e., without pretreatments, and employing safe processing conditions and short growth time. The morphological, spectroscopic and electrical characterization of graphene-coated samples (Fig.1), were carried out as-processed and after natural aging. We demonstrated that the conductivity of Cu wire is enhanced upon annealing, due to the increased crystallinity, whereas graphene can protect the substrate from oxidation, leading to high performances maintained over time. In particular graphene coating enable a 0.7-2.0% improvement on conductivity, with respect to pristine Cu wires, after 1 year aging time. Furthermore, the optimisitation of CVD process on lab scale paves the way for the effective industrial application of graphene-based coatings, exploiting the true benefits of roll-to-roll manufacturing.