A Novel Solvent-free Room Temperature Molten Salt Electrolyte Based on LiODFB and 2-Oxazolidinone for EDLCs

Abstract A series of new room temperature molten salt electrolyte based on lithium oxalyldifluoroborate (LiODFB) and 2-Oxazolidinone (C 3 H 5 NO 2 , OZO) for EDLCs were synthesized by a facile and fast route. The investigation of the electrochemical characteristics of LiODFB-OZO molten salt electrolytes and the evaluation of LiODFB-OZO complex as electrolyte for EDLCs shows that the resulting molten salt exhibits excellent thermal stability, high ionic conductivity (up to ∼ 12.8 mS cm – 1 ), a wide electrochemical stability window (∼ 3.8 V) and lower electron-transfer resistance (∼ 4.8 Ω).The EDLCs with the LiODFB-OZO complex electrolyte can be charged up to 3.0 V. At 30°C the EDLCs with LiODFB-OZO complex electrolyte based on activated carbon electrodes deliver a stable specific capacitance of ∼ 83.9 F g – 1 ; At 70°C, they can deliver stable capacities of up to ∼ 106.1 F g – 1 (current density, 1 mA cm – 2 ). It is reasonable to assume that LiODFB-OZO complex system has some advantages as electrolyte for EDLCs with high energy density and high-power density, especially at elevated temperatures.