Water in Solvate Ionic Liquids: Preserving Lithium Coordination While Enhancing Ionic Conductivity

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Solvate ionic liquids (SILs) offer unique properties but often suffer from high viscosity.
• Water-in-salt (WIS) electrolytes demonstrate enhanced ionic conductivity.
• Combining SILs and WIS concepts could lead to advanced electrolyte materials.

Purpose of the Study:

• To investigate the creation of hybrid electrolyte systems by merging SILs and WIS electrolytes.
• To explore the effects of water addition on the properties of a specific SIL, [Li(G3)][NTf2].
• To characterize the structure and electrochemical performance of the resulting hybrid systems.

Main Methods:

• Molecular dynamics simulations were employed to model electrolyte behavior.
• Experimental techniques were used to validate simulation findings.
• Electrochemical measurements assessed conductivity and stability.

Main Results:

• The addition of equimolar water to the neat SIL [Li(G3)][NTf2] significantly reduced viscosity and increased ionic conductivity.
• Water molecules were found to be individually incorporated into cationic complexes, preventing water network formation.
• The resulting water-in-solvate-ionic-liquid (WISIL) electrolytes maintained a wide electrochemical stability window (4.9 V).

Conclusions:

• Hybrid WISIL electrolytes offer a promising route to overcome the limitations of neat SILs.
• These electrolytes exhibit improved transport properties and maintain excellent electrochemical stability.
• WISIL electrolytes represent a new class of advanced materials for electrochemical applications.