Networks of Graphene Nanoribbons and Nanosheets Formed in Metals by the Electrocharging Assisted Process

The incorporation of carbon nanostructures, such as graphene and carbon nanotubes, in the lattice of metals is desirable to take advantage of the superior mechanical and electrical properties of these graphitic nanostructures and the high density of electrons in metals. There have been numerous attempts to create composites of metals, such as copper or aluminum, with carbon nanostructures. These methods frequently require several steps and in aluminum produce the undesirable compound Al₄C₃. We use electrocharging assisted process which creates graphene nanoribbons and nanosheets in a metal by the application of a high DC current of ~150 A to a mixture of the liquid metal and particles of activated carbon. The graphitic structures bond with atoms in the metal making the composite very stable. Raman scattering, X-ray photoelectron spectroscopy, and electron energy loss spectroscopy indicate sp2 bonding of the carbon and TEM images show graphene nanoribbons and nanosheets in the lattice of the metal. The electrical conductivity of Al covetic with 3 wt % C increased by ~20% and the thermal conductivity of copper with ~3 wt % C increased by ~13%. Films of Cu with C are more transparent and resistant to oxidation than pure copper films.