Physical and electrolytic properties of difluorinated dimethyl carbonate

The physical and electrolytic properties of difluorinated dimethyl carbonate (DFDMC) synthesized using F2 gas (direct fluorination) were examined. The dielectric constant and viscosity of DFDMC are higher than those of monofluorinated dimethyl carbonate (MFDMC) and dimethyl carbonate (DMC). The oxidative decomposition voltage of DFDMC is higher than those of DMC and MFDMC. The specific conductivity in DFDMC solution is considerably lower than those in MFDMC and DMC solutions. The ethylene carbonate (EC)-DFDMC equimolar binary solution containing 1 mol dm−3 LiPF6 shows a moderate conductivity of 6.91 mS cm−1 at 25 °C. The lithium electrode cycling efficiency (charge–discharge coulombic cycling efficiency of lithium electrode) in EC-DFDMC equimolar binary solution containing 1 mol dm−3 LiPF6 is higher than 80%. The EC-DFDMC solution is a good electrolyte for rechargeable lithium batteries.