Intercalation chemistry of graphite fluorides

Abstract

Graphite fluorides of the general composition CF n , with n  0.25−1.0, are found, according to X-ray diffraction and X-ray photoelectron studies, to contain graphitic zones which allow oxidative intercalation by bis(fluorosulfuryl)peroxide, S 2O 6F 2, as well as intercalation by fluorosulfuric acid HSO 3F and trifluoromethylsulfuric acid HSO 3CF 3. The reactions produce materials of the general composition CF n (SO 3F) m or CF n (HSO 3X) m , with X  F or CF 3. While intercalation of S 2O 6F 2 into the graphitic zones results in the formation of first-stage intercalation products in all instances, higher-stage materials form with HSO 3F and to an increased degree with HSO 3CF 3, particularly when graphite fluorides with low fluorine contents are used. Interestingly, according to their X-ray photoelectron spectra, intercalation of all three reagents causes an increase in the polarity of the C—F bond; the oxidized graphitic zones appear to increase while the fluorine ls binding energies suggest an increased ionic character.