Conductive enhancement of copper/graphene composites based on high-quality graphene

Copper is a well-known traditional metal and has been widely used for thousands years due to its combination of properties, especially its electrical conductivity. Any efforts to increase copper's electrical conductivity, by even a small percentage, will make a great contribution to the economic effectiveness of society. In this paper, we report an electrical conductivity enhanced copper/graphene composite based on high-quality graphene (HQG) via processes involving graphene-coated copper powders through ball milling, and subsequent spark plasma sintering (SPS). The HQG is converted from regular reduced graphene oxide (RGO) by using a hot-pressing treatment. The experimental results reveal that: (1) on comparing with the copper/RGO composite, the electrical conductivity of the copper/HQG composites is significantly increased; (2) the highest electrical conductivity of the copper/HQG composite was obtained at the optimal mass percentage, 1 wt%, of HQG, at which an 8% increase was achieved when compared with pure copper. We believe that the electrical conductivity enhancement is related to the high electron mobility of HQG, and the formation of a graphene conductive network in the copper/HQG composites. In addition, the hardness of both the copper/RGO and copper/HQG composites is much higher than that of pure copper, while the copper/HQG composite shows the highest value when the amount of HQG is 0.5 wt%. It is expected that the copper/HQG composites have broad prospects of application in the electrical and electronics industry, light industry, machinery manufacturing, architecture construction, national defense, etc.