Electrical Double Layer Structure in Ionic Liquids and Its Importance for Supercapacitor, Battery, Sensing, and Lubrication Applications

The performance of electric double-layer capacitors is strongly influenced by the choice of electrolyte, and electrolytes comprised of ionic liquid mixtures have shown promise for enabling high energy densities. Here we perform all-atom molecular dynamics simulations of ionic liquids containing 1-ethyl-3-methylimidazolium and different fractions of bis(trifluoromethylsulfonyl)imide and tetrafluoroborate, in conjunction with planar graphene sheets as electrodes. We demonstrate that relative ion–electrode van der Waals interactions play an important role in the population of ions adsorbed in the first interfacial layer near uncharged electrodes. Near charged electrodes, we find that the ionic liquid mixtures generally exhibit integral capacitances intermediate between the two pure ionic liquids. We characterize cumulative ion densities near electrodes carrying various surface charges, revealing different charging mechanisms for different ionic liquids, which we relate to the relative sizes of the ions. Finally, in the ionic liquid mixtures we identify an effective ion exchanging phenomenon wherein charging of the electrodes leads to different trends in the densities of the two types of anions in the first interfacial layer, which enhances counterion adsorption and improves capacitance at the negative electrode.

Simulation Study of the Capacitance and Charging Mechanisms of Ionic Liquid Mixtures near Carbon Electrodes

Replacing conventional aqueous-based electrolytes with room-temperature ionic liquids (RTILs) for electrochemical applications is a major research focus. However, in applications where RTILs are ex...

Effect of Humidity and Impurities on the Electrochemical Window of Ionic Liquids and Its Implications for Electroanalysis

Ionic liquids in wastewater treatment: A review on pollutant removal and degradation, recovery of ionic liquids, economics and future perspectives

The oxygen reduction reaction (ORR) is widely studied in room-temperature ionic liquids (RTILs) but typically in dry environments. Because water is known to affect diffusion coefficients and reacti...

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Simon Doblinger

Papers

Electrical Double Layer Structure in Ionic Liquids and Its Importance for Supercapacitor, Battery, Sensing, and Lubrication Applications

Effect of Humidity and Impurities on the Electrochemical Window of Ionic Liquids and Its Implications for Electroanalysis

Effect of Ionic Liquid Structure on the Oxygen Reduction Reaction Under Humidified Conditions

Functionalized Imidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquids for Gas Sensors: Solubility of H2, O2 and SO2

Detection of sulfur dioxide at low parts-per-million concentrations using low-cost planar electrodes with ionic liquid electrolytes