Electrochemically cathodic exfoliation in room temperature ionic liquids N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF2N) has been developed for few-layer graphene sheets, demonstrating low levels of oxygen (2.7at% of O) with a nearly perfect structure (I D/I G <0.05). The mechanism of cathodic exfoliation in BMPTF2N involves the intercalation of ionic liquids cation [BMP]+ under highly negatively charge followed by graphite expansion. Porous activated graphene sheets were also obtained by activation of graphene sheets in KOH. Transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize these graphene materials. The electrochemical performances of the graphene sheets and porous activated graphene sheets for lithium-ion battery anode materials were evaluated using cyclic voltammetry, galvanostatic charge–discharge cycling, and electrochemical impedance spectroscopy.