Electrolytes based on alkoxysilyl-functionalized ionic liquids: viscoelastic properties and conductivity.

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Ionic liquids (ILs) are promising electrolytes for electrochemical devices, particularly in quasi-solid states.
• The sol-gel process offers a viable method for solidifying ionic liquids into functional electrolytes.

Purpose of the Study:

• To synthesize alkoxysilyl-functionalized imidazolium-based ionic liquids for quasi-solid electrolytes.
• To investigate the gelation process and microstructure of these ionic liquids using the sol-gel method.
• To correlate the viscoelastic properties of the resulting gels with their ionic conductivity.

Main Methods:

• Synthesis of alkoxysilyl-functionalized iodide imidazolium-based ionic liquids.
• Preparation of quasi-solid electrolytes by mixing functionalized ILs with 1-methyl-3-propylimidazolium iodide (MPIm(+)I(-)).
• In situ and ex situ rheological studies to monitor sol-gel transition and analyze viscoelastic properties.
• Measurement of ionic conductivity of the prepared electrolytes.

Main Results:

• Successful formation of three-dimensional sol-gel networks with varying microstructures and viscoelastic properties.
• Correlation established between rheological parameters (elastic modulus, viscous contribution, phase shift) and ionic conductivity.
• Achieved ionic conductivity of approximately 10(-3) S cm(-1) at room temperature for gels with significant elastic modulus and viscous contribution.

Conclusions:

• Alkoxysilyl-functionalized ionic liquids are effective in forming quasi-solid electrolytes through sol-gel processing.
• The viscoelastic behavior, including the interplay between viscous and elastic moduli and gelation time, is critical for high ionic conductivity.
• The study highlights the importance of tailored sol-gel network properties for optimizing ionic liquid-based electrolytes.