This site was last updated on 11th Feb 2019

Structure and dynamics of ionic liquids

Structure and dynamics of ionic liquids

Ion-Image Interactions and Phase Transition at Electrolyte-Metal Interfaces

We showed the ion-image interactions could explain the phase transition on electrolyte-metal interfaces and concomitant divergence in capacitance observed in recent simulations. Moreover, we show how diluted ionic liquid could maximise capacitance whilst avoiding the hysteresis that accompanies the phase transition.

The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration

We showed that the decay length of the disjoining force between charged surfaces in an electrolyte solution increases with ion concentration. With ion diameters ~0.5nm, the decay length can be ~10nm for ionic liquids. 

Dynamics of Ion Transport in Ionic Liquids

We derived a continuum electrokinetic framework for ionic liquids by coarse graining a simple exclusion process defined on a lattice. Our framework reveals new regimes of charging that is qualitatively different to classic mean-field electrokinetics. 

Are Room Temperature Ionic Liquid Dilute Electrolytes?

We developed a thermodynamic model to understand the extent of ion pairing in room temperature ionic liquids. Our model addresses a significant debate in the literature and provides a powerful way to model physical properties of ionic liquids. 

Unravelling Nanoconfined Films of Ionic Liquids

We used a 1D Coulomb gas model to understand the thermodynamic properties of ionic liquids confined between charged surfaces. 

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Scaling analysis of the screening length in concentrated electrolytes

We developed a scaling theory which shows why the electrostatic correlation length in concentrated electrolytes could be an order of magnitude larger than the ion diameter. We also showed that the electrostatic correlation length is directly related to bulk thermodynamic properties such as the activity coefficient. 

Switching the structural force in ionic liquid-solvent mixtures by varying composition

We showed that the wavelength of the structural force in ionic liquid-solvent mixtures vary abruptly with composition. 

Ion-image interactions and phase transition at electrolyte-metal interfaces

We showed that ion-image interactions could explain the phase transition on electrolyte-metal interfaces and concomitant divergence in capacitance observed in recent simulations. Moreover, we show how diluted ionic liquid could maximise capacitance whilst avoiding the hysteresis that accompanies the phase transition.

The electrostatic screening length in concentrated electrolytes increases with concentration

We showed that the decay length of the disjoining force between charged surfaces in an electrolyte solution increases with ion concentration. With ion diameters ~0.5nm, the decay length can be ~10nm for ionic liquids. 

Dynamics of ion transport in ionic liquids

We derived a continuum electrokinetic framework for ionic liquids by coarse graining a simple exclusion process defined on a lattice. Our framework reveals new regimes of charging that is qualitatively different to classic mean-field electrokinetics. 

Are room temperature ionic liquids dilute electrolytes?

We developed a thermodynamic model to understand the extent of ion pairing in room temperature ionic liquids. Our model addresses a significant debate in the literature and provides a powerful way to model physical properties of ionic liquids. 

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Nanoporous Supercapacitors

Capacitance-Power-Hysteresis trilemma in nanoporous supercapacitors

Using a simple mean-field model, supported by Monte Carlo simulations, we unraveled a parameter regime where the capacitance of nanoporous supercapacitors can be optimised without sacrificing the kinetics of charging and without hysteretic energy loss due to irreversible phase transitions. 

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Quantum capacitance modifies interionic interactions in semiconducting nanopores 

We showed that the interionic interaction in carbon nanotubes and graphene slit pore is much longer-ranged than ideal metallic tubes/slits. Our work suggests that the electronic structure of the electrode material plays a significant role in determining the capacitance of nanoporous supercapacitors. 

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Single-file charge storage in conducting nanopores

We used a lattice model to investigate the mechanism of charge storage in cylindrical nanopores. We identified "ionophilicity", the non-electrostatic interaction energy between nanotube and ions, as the key control parameter for optimising charge storage. 

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Charging dynamics of supercapacitors with narrow cylindrical nanopores

We derived kinetic equations for ion transport in a narrow nanopores from systematic coarse-graining of the microscopic dynamics.  Our equations reveal the nanoscale traffic of ions in and out of the nanotube, and suggest strategies to prevent "congestion".

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