Structure-Property Correlation in Phenyl N-Substituted Imidazolium Protic Ionic Liquids.

Area of Science:

• Materials Science
• Chemical Engineering
• Electrochemistry

Background:

• Understanding structure-property relationships in protic ionic liquids (PILs) is crucial for their targeted design.
• Recently developed PILs, benzylimidazolium bis(trifluoromethylsulfonyl)imide and n-phenylimidazolium bis(trifluoromethylsulfonyl)imide, require thorough characterization.

Purpose of the Study:

• To investigate the impact of a phenyl group addition to the cation of PILs on their physicochemical properties.
• To compare these novel PILs with the archetypal 1-ethylimidazolium bis(trifluoromethylsulfonyl)imide.

Main Methods:

• Comprehensive experimental characterization including phase behavior, thermal stability, intermolecular interactions, transport properties, and electrochemical performance.
• Utilizing a wide range of established experimental techniques.

Main Results:

• The introduction of a phenyl group led to decreased thermal stability and lower ionic conductivity.
• Increased viscosity and stronger intermolecular interactions were observed with the phenyl-substituted PILs.
• Comparable fragility and an enhanced electrochemical stability window were maintained.

Conclusions:

• The phenyl group significantly influences the properties of PILs, offering a route to tune their performance.
• These findings provide valuable insights for the rational design of PILs with tailored electrochemical and transport properties.