Lithium perfluoroalkylphosphonate was synthesized by LiF and perfluoroalkylphosphonate acid obtained by electrochemically fluorinating chlorodiisopropylphosphine. Some properties of a kind of electrolyte that was made from dissolving the lithium perfluoroalkylphosphonate in the mixed solvent with ethylene carbonate (EC) and dimethyl carbonate (DMC) mass ratio 1∶1 were investigated, such as conductivity, stability toward hydrolysis and oxidative decomposition potential, and so on. The electrolyte was studied by a secondary cell testing system. Using LiCoO2 as anode, Li as cathode, it was found that the discharge platform was 3.7 V, initial discharge capacity was 107 mA•h•g－1 and efficiency still remained 102% after cycled 50 times while capacity decreased largely after 40 times. The electrochemical impedance spectroscopy diagram showed that the electrolyte electrochemical impedance was nearly 140 Ω. The results indicated that the lithium perfluoroalkylphosphonate was expected to be the new electrolyte salt of lithium-ion rechargeable batteries.

Key words: electrochemical fluorination, Li-ion secondary battery, lithium perfluoroalkylphosphonate