Fluorographene, a cousin of graphene, not only inherits the excellent mechanical properties of graphene but also has great unique application potential in high-performance devices and materials, such as lubricating agents, digital transistors, nanocomposites, and energy-storage devices. However, large-scale preparation of fluorographene remains a great challenge. Herein, an easy-operating, highly scalable, and low-cost approach was reported for the preparation of fluorographene using commercially available fluorographite as the starting material. In this procedure, fluorographite turned into few-layer fluorographene through a rapid exfoliation process with Na₂O₂ and HSO₃Cl as exfoliating agents. The whole preparation process was performed in air and without heating, sonication, and protective gas. The obtained fluorographene was characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, ¹⁹F nuclear magnetic resonance spectroscopy, X-ray diffraction, thermogravimetric analysis, atomic force microscopy, and transmission electron microscopy, and it possesses a hexagonal polycrystalline structure. Fluorographene and fluorographite were employed as cathode materials of the primary lithium battery, and it was found that the specific discharge capacity of the battery using fluorographene was improved remarkably compared to that using fluorographite. Cyclic voltammetry results also showed that specific capacitances of fluorographene were dozens of times higher than that of fluorographite. It is clear that electrochemical properties of fluorographene are significantly improved against fluorographite.