Binary molten salt electrolytes based on LiClO₄ and 2-oxazolidinone

Novel binary molten salt electrolytes based on LiClO₄ and 2-oxazolidinone (OZO) were prepared. The electrolytes appeared as liquid at room temperature though they were composed of two solids. DSC analysis showed that the LiClO₄-OZO electrolyte was liquid with a eutectic temperature about -50 °C. FTIR spectroscopy indicated that OZO could coordinate with Li+ cation in the LiClO₄-OZO system through Li-O bonding. A big coordinate cation was formed and the coulombic force was weakened. Meanwhile, Li-O coordination could also lead to the breakage of hydrogen bonding between OZO molecules, resulting in the decrease of the eutectic temperature of the system compared with pure salt. Some the molten salt samples existed as liquid state at room temperature. The electrochemical properties were evaluated by ac impedance spectroscopy and cyclic voltammertry, respectively. The conductivity of LiClO₄-OZO electrolyte at molar ratio of 1:4.5 was 0.66×10-3 S· cm^-1 at 25 °C and 7.33×10^-3 S· cm^-1 at 80 °C, and the electrochemical window was about 3.5 V.