Preparation, Characterization, and Exfoliation of Graphite Perfluorooctanesulfonate

Air-stable graphite compounds with perfluorooctanesulfonate, C x C 8 F 17 SO 3, are prepared by electrochemical oxidation of HOPG chips or SP-1 graphite powder in LiC 8 F 17 SO 3 (saturated)/CH 3 NO 2 electrolyte. XRD patterns of several single-stage products indicate that highly ordered intercalation compounds form with d i = 24.6−24.9 Å for stages ( n ) = 3−7 or 26.6 Å for n = 2, supporting the model of a bilayer of perfluoroalkylsulfonate anions within the intercalated galleries. Gravimetric and thermogravimetric data provide x for n = 2−6. Consistent with the bilayer model, the C/anion ratio is found to be much lower than in small-anion intercalation compounds. Ambient temperature exfoliation occurs when a high-stage graphite sulfate is anodized in the C 8 F 17 SO 3 - -containing electrolyte.