Electrochemical Formation of a Covalent–Ionic Stage‑1 Graphite Intercalation Compound with Trifluoroacetic Acid

A pure stage-1 graphite intercalation compound (GIC) has been prepared by the electrochemical oxidation of graphite in trifluoroacetic acid (CF₃COOH). During the CF₃COOH-GIC formation, covalent as well as ionic bonds between the trifluoroacetic acid and graphite layers are formed. Electrochemical reduction of the stage-1 GIC leads to the deintercalation of ionically bonded intercalate, yielding the stage-2 covalent GIC. The interlayer spacing is 8.10 Å for stage-1 and 11.62 Å for stage-2 GIC. Further electrochemical oxidation of stage-1 CF₃COOH-GIC does not lead to the exfoliation of the GIC product, and the GIC has relatively high stability in air.