Production of graphene by liquid-phase exfoliation of intercalated graphite

Abstract

Liquid-phase exfoliation of tetraethylammonium graphite intercalation compound (TEA-GIC) has been prepared by high-power tip-sonication of graphite in aqueous TEA solution. The release of gaseous species due to the decomposition of TEA under microwave irradiation led to huge expansion of graphite. The expanded graphite was then exfoliated to produce graphene under mild sonication in organic solvents. Raman and X-ray photoelectron spectroscopy measurements indicated that the thus prepared graphene had few defects and little oxidation. In addition, the graphene films exhibited an electrical conductivity of 5000 S m-1 and the production process is easy to scale up and the single-cycle yield reached is as high as 5%.