Liquid-phase exfoliation of fluorinated graphite to produce high-quality graphene sheets

Chemical exfoliation of graphite as a facile method is used to synthesize graphene sheets on a large scale. However, the preparation process including oxidation of graphite and reduction of graphene oxide causes many defects and unnecessary oxygen-containing groups in obtained graphene sheets. In this study, a simple and facile method is proposed to create graphene starting from fluorinated graphite (FGi). Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and transmission electron microscopy were employed to analyze the components and structure of the graphene sheets. The results showed that large and flat graphene sheets with the polycrystalline structure were obtained by the chemical exfoliation of FGi. The F/C ratio can be facilely tuned just by adjusting the refluxing time, and the ratio is almost not decreased when reaction time is more than 8 h. Furthermore, the electrical conductivity and electrochemical properties of the as-prepared graphene have been systematically investigated and exhibited regularity with a variation of the F/C ratio.