Effect of dissolved LiCl on the ionic liquid-Au(111) electrical double layer structure.
Robert Hayes1, Natalia Borisenko, Brendan Corr
1Centre for Advanced Particle Processing, The University of Newcastle, Callaghan, NSW 2308, Australia.
Chemical Communications (Cambridge, England)
|September 13, 2012
Summary
Models for electrical double layers in ionic liquids (ILs) may fail when solutes like LiCl are present. Dissolving small amounts of LiCl significantly weakens interfacial ion layering at IL-Au(111) interfaces across a wide potential range.
Area of Science:
- Electrochemistry
- Surface Science
- Materials Science
Background:
- The electrical double layer (EDL) at electrode-electrolyte interfaces is crucial for electrochemical processes.
- Ionic liquids (ILs) offer unique properties as electrolytes, with structured EDLs.
- Understanding the influence of solutes on IL-based EDLs is vital for applications.
Purpose of the Study:
- To investigate the effect of lithium chloride (LiCl) as a solute on the electrical double layer structure at ionic liquid-gold(111) interfaces.
- To determine how LiCl concentration impacts interfacial ion layering.
- To assess the validity of existing EDL models for pure ILs in the presence of solutes.
Main Methods:
- Electrochemical characterization of Au(111) electrodes in contact with ionic liquids.
- Varying the concentration of LiCl dissolved in the ionic liquid.
- Potentiodynamic sweeps across a potential range of -2.0 V to +2.0 V (vs. Pt).
- Analysis of interfacial structure through electrochemical measurements.
Main Results:
- The electrical double layer at the ionic liquid-Au(111) interface typically exhibits alternating ion layers.
- Dissolving even small amounts of LiCl markedly weakens this interfacial layering.
- This weakening effect is observed across the entire potential range studied (-2.0 V to +2.0 V).
Conclusions:
- Interfacial ion layering in ionic liquid-Au(111) systems is sensitive to the presence of solutes.
- Standard models developed for pure ionic liquid EDLs may not accurately represent systems with dissolved salts.
- The findings highlight the need for revised models to account for solute effects in ionic liquid electrochemistry.
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