M.J. Green, T.C. Achee, J.T. Hope, W. Sun, P. Lakhe
Texas A&M University,
Keywords: graphene, nanosheet, oxidation, exfoliation, production
Summary:Electrochemical exfoliation is a promising bulk method for producing graphene from graphite; in this method, an applied voltage drives ionic species to intercalate into graphite where they form gaseous species that expand and exfoliate individual graphene sheets. However, a number of obstacles have prevented this approach from becoming a feasible production route; the disintegration of the graphite electrode as the method progresses is the chief difficulty. Here we show that if graphite powders are contained and compressed within a permeable and expandable containment system, the graphite powders can be continuously intercalated, expanded, and exfoliated to produce graphene. Our data indicate both high yield (65%) and extraordinarily large lateral size (>30 μm) in the as-produced graphene. We also show that this process is scalable and that graphene yield efficiency depends solely on reactor geometry, graphite compression, and electrolyte transport. The resulting material is significantly less oxidized than typical Hummers’ Method graphene oxide and avoids many of the safety and scalability issues associated with graphene oxide production.