Electric double layer capacitors (EDLCs) have been assembled with carbon nanotubes (CNTs) as the electrodes and a novel binary room temperature molten salt (RTMS) composed of lithium bis(trifluoromethane sulfone)imide (LiN(SO2CF3)2, LiTFSI) and acetamide as the electrolyte. The electrochemical performances of the RTMS and the EDLC are evaluated with cyclic voltammetry (CV), ac impedance spectroscopy and galvanostatic charge/discharge, etc. The EDLC with these components show excellent electrochemical properties in specific capacitance, rate and cycling performances at ambient and elevated (60°C) temperatures, indicating that RTMS is a promising electrolyte for advanced EDLCs.