The two-step synthesis of sodium (2,3,5,6-tetrafluorophenoxy) diethane sulfonate (Na-TFP) is reported, starting from 2,3,5,6-tetrafluorohydroquinone as the precursor. Compared with conventional aqueous electrolytes such 0.5 m NaClO4 and Na2SO4, solution Na-TFP provides higher ionic conductivity over a wide range temperature (e.g., >60 mS cm−1 at 20 °C >70 30 °C) wider electrochemical stability ...