Electrolyte based on fluorinated cyclic quaternary ammonium ionic liquids

International audienceIonic liquids, ILs, based on fluorinated pyrrolidi- nium and piperidinium ammonium cations and imide anion were prepared and characterized. The physicochemical and electrochemical properties of these ILs including melting point, glass transition and degradation temperatures, viscosity, ionic conductivity, and electrochemical stability were deter- mined and compared to alkyl pyrrolidinium and piperidinium ILs. The incorporation of a CF3 group instead of a CH3 induces an increase of the IL viscosity, thus a conductivity decrease. However, good ionic conductivity is obtained with fluorinated pyrrolidinium IL. Cyclic amine ILs with propyl alkyl chain or fluorinated ammonium exhibit very high electrochemical sta- bility toward oxidation. The effect of the addition of LiTFSI on the IL properties was studied with the same methodology