Influence of Introducing a Benzyl Group on Physical and Electrochemical Properties of Bis(fluorosulfonyl)amide-Based Phosphonium Ionic Liquids

Abstract

The physical and electrochemical properties of room-temperature ionic liquids based on quaternary phosphonium cations containing a benzyl group in combination with bis(fluorosulfonyl)amide anion. It was found that the benzylphosphonium RTILs showed lower melting points, lower viscosities and higher conductivities than those of the corresponding TFSA-based benzylphosphonium and ammonium RTILs. The thermal stability of the benzyl-phosphonium RTILs was significantly improved by introducing a phenyl group into the phosphonium cations. The introduction of a phenyl group tended to reduce the electrochemical stability of the benzylphosphonium RTILs.