In this research, we investigated the potential application of vinyl ethylene carbonate (VEC) and ethylene carbonate (EC) as solid electrolyte interface (SEI) film-forming additive in 1-ethyl-3-methylimidazolium (EMI)-bis(trifluoromethyl-sulfonyl) imide (TFSI)-LiTFSI ionic liquid electrolyte (IL). The electrochemical performance of natural graphite (NG7) was studied in LiTFSI/EMI-TFSI containing different weight percent of EC/VEC via cyclic voltammetry (CV), electrochemical impedance spectrum (EIS), and galvanostatic charge/discharge cycles. Temperature effect on the discharge/charge performance of NG7 electrode in the researched IL electrolyte was also discussed.