Physical and electrochemical properties of new binary room-temperature molten salt electrolyte based on LiBETI and acetamide

A new binary room-temperature molten salt electrolyte based on lithium bis(perfluoroethysulfonyl) imide (LiN(SO2C2F5)2, LiBETI) and acetamide has been prepared and characterized by differential scanning calorimetry (DSC), IR, Raman spectroscopy, ac impedance, and cyclic voltammetry, etc. Both LiBETI and acetamide are solid, but their mixture is a liquid at room temperature with a eutectic temperature of −57 °C at a molar ratio of 1:4. The formation of this new room-temperature molten salt (RTMS) is due to strong interaction between the two components, as confirmed by IR and Raman spectroscopy. The conductivity behaviour consists with the VTF equation. The ionic conductivity of LiBETI/acetamide complex at a molar ratio of 1:6 reaches 1.27×10−3 S/cm at 30 °C, much higher than 4.06×10−4 S/cm of another similar system of LiTFSI/urea system reported by us previously. The reduction and oxidation potentials of this RTMS were observed at 0.6 and 3.8 V vs. Li/Li+, respectively.