Mechanochemical Delamination of Graphite in the Presence of Various Inorganic Salts and Formation of Graphene by Its Subsequent Liquid Exfoliation

Feasibility was demonstrated for the mechanochemical delamination of graphite in the presence of inorganic salts such as NaCl, Na2SO4, and CaCO3 with subsequent liquid exfoliation of the resultant nanostructurized graphite materials to produce graphene. The nature of the inorganic delaminating agents, in particular, their hardness, may have a significant effect on the structural defectivity in the graphenes obtained and their capacity to form stable dispersions in various solvents. Sodium sulfate proved to be the most generally useful agent among the inorganic salts tested. The use of sodium sulfate leads to stable graphene dispersions in N-methylpyrrolidone, dimethylformamide, ethanol, and water.