Joint-Linker Type Ionic Gels Using Polymerizable Ionic Liquid as a Crosslinker via Thiol-Ene Click Reactions

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Development of advanced electrolytes is crucial for next-generation energy storage devices.
• Ionic liquids offer unique properties as electrolytes but often require suitable matrices for practical application.

Purpose of the Study:

• To synthesize novel ion-conductive gels (ionic gels) using thiol-ene click reactions.
• To investigate the influence of monomer structure and composition on gel properties.
• To evaluate the potential of these ionic gels as electrolytes.

Main Methods:

• Synthesis of ionic gels via photopolymerization of multifunctional thiol monomers (TEMPIC, PEMP, DPMP) and a bifunctional allyl ionic liquid crosslinker.
• Characterization using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), compression testing, and impedance spectroscopy.
• Investigating the effect of monomer functionality and Li+ ion content on ionic conductivity.

Main Results:

• Successful synthesis of ionic gels with tunable mechanical and conductive properties.
• Good thermal stability observed up to 100 °C.
• Achieved an ionic conductivity of 4.89 mS cm⁻¹ at room temperature with low-functional thiol monomers.
• Demonstrated increased ionic conductivity with higher Li+ ion content and elevated temperatures.

Conclusions:

• Thiol-ene click chemistry provides an effective route for creating ion-conductive polymer gels.
• The properties of the ionic gels are highly dependent on the choice and functionality of the thiol monomers.
• These ionic gels show promise as solid-state electrolytes for electrochemical applications.