The invention discloses a method for electrochemical synthesis of
lithium imidodifluorosulfonate. The preparation method comprises: regulating the temperature of an electrolytic tank to 0-18 DEG C, respectively taking two
nickel plates as an
anode and a
cathode, adding a proper amount of
anhydrous hydrofluoric acid into the electrolytic tank, and carrying out
electrolysis; after the current in theelectrolytic tank is stabilized, adding a proper amount of imidodichlorosulfonate into the electrolytic tank, and after the imidodichlorosulfonate is dissolved, adjusting the working
voltage of the electrolytic tank to 5-8 V; when the current is reduced to below 5 mA, taking out the solution in the electrolytic tank; distilling the solution taken out from the electrolytic tank under normal pressure to separate the imidodifluorosulfonate from the
anhydrous hydrofluoric acid, and cooling to obtain the high-purity colorless liquid imidodifluorosulfonate; and reacting with
lithium hydroxide, filtering, and re-crystallizing to obtain high-purity
lithium imidodifluorosulfonate. According to the invention, water and
chlorine ions are electrochemically pre-removed while fluorination is performedthrough
electrochemistry without introduction of a
metal halide as a catalyst, so that the method is simple in process, low in
energy consumption and low in cost, and the prepared LiFSI is high in purity.