A mean-field theory on the differential capacitance of asymmetric ionic liquid electrolytes. II. Accounts of ionic interactions

Yin, Li; Huang, Yike; Chen, Houxian; Yan, Tianying

doi:10.1039/c8cp02943a

Cited by 18 publications

(15 citation statements)

References 13 publications

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“…They give a possibility to consider systems beyond the assumptions of continuum models and to take into account a wide spectrum of interparticle interactions as well as to predict correlation effects using the statistical mechanics. It was shown that the voltage dependence of the differential capacitance obtained within the mean field approximation for the case of short-range interactions between ions is closer to experimental findings [47,48]. The importance of short-range interactions in a lattice model of ionic systems was demonstrated in [49], where the effect of competition between long-range Coulomb and short-range dispersion interaction on phase transitions was studied.…”

Section: Introductionsupporting

confidence: 59%

The effect of short-range interaction and correlations on the charge and electric field distribution in a model solid electrolyte

et al. 2019

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A simple lattice model of a solid electrolyte presented as a xy-slab geometry system of mobile cations on a background of energetic landscape of the host system and a compensating field of uniformly distributed anions is studied. The system is confined in the z-direction between two oppositely charged walls, which are in parallel to xy-plane. Besides the long-range Coulomb interactions appearing in the system, the short-range attractive potential between cations is considered in our study. We propose the mean field description of this model and extend it by taking into account correlation effects at short distances. Using the free energy minimization at each of z-coordinates, the corresponding set of non-linear equations for the chemical potential is derived. The set of equations was solved numerically with respect to the charge density distribution in order to calculate the cations distribution profile and the electrostatic potential in the system along z-direction under different conditions. An asymmetry of charge distribution profile with respect to the midplane of the system is observed. The effects of the short-range interactions and pair correlations on the charge and electric field distributions are demonstrated.

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Section: Introductionsupporting

confidence: 59%

The effect of short-range interaction and correlations on the charge and electric field distribution in a model solid electrolyte

et al. 2019

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“…Extremely high ion concentrations in ionic liquids strongly increase the importance of short-range interactions and correlations. It was shown that with accounting of the short-range interactions on the mean field level in addition to the Coulomb ones the voltage dependence of the differential capacitance becomes closer to experimental findings [24,25]. An important influence of a competition of short-range dispersion (or van der Waals) and long-range Coulomb interactions on phase transitions in a lattice model of ionic systems was demonstrated in [26].…”

Section: Introductionmentioning

confidence: 59%

Short- and long-range contributions to equilibrium and transport properties of solid electrolytes

Bokun¹,

Kravtsiv²,

Holovko³

et al. 2019

Condens. Matter Phys.

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Condensed ionic systems are described in the framework of a combined approach that takes into account both long-range and short-range interactions. Short-range interaction is expressed in terms of mean potentials and long-range interaction is considered in terms of screening potentials. A system of integral equations for these potentials is constructed based on the condition of the best agreement of the system of study with the reference system. In contrast to the description of media with short-range interactions, in this text the reference distribution includes not only the field of mean potentials but also Coulomb interaction between particles. A one-component system made of ions in a neutralizing background of fixed counterions is considered. The model can be used to describe solid ionic conductors. In order to study the movement of cations on the sites of their sub-lattice, the lattice approximation of the theory is employed based on the calculation of the pair distribution function. Using the collective variables approach, a technique improving the starting expression for this function is proposed. Notably, the neglected terms in the expansion of this function are approximated by single-particle terms ensuring that the normalization condition is satisfied. As a result, the applicability of the theory is extended to a wide region of thermodynamic parameters. The chemical potential and the diffusion coefficient are calculated showing the possibility of phase transitions characteristic of the system.

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“…[11] In addition, a series of simulations have established the models which include the contribution of C H and C D (diffuse layer capacitance) to describe the experimental results of SLG in aqueous electrolytes. [12] It was found that the interfacial capacitance of polarized SLG electrodes changes with the degree of ion packing (the total number of anions and cations in the electrolyte bulk divided by total number of available sites at the electrode surface), ion-ion interaction (through a correlation length parameter) and size of ions in neat ionic liquids. [13] For instance, when the ion packing factor is high, C Q would control the interfacial capacitance near the potential of zero charge (pzc) without seeing the effect of ion-ion correlation, resulting in a camel-shape dependence of the total capacitance on the applied potential.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Characterization of Single Layer Graphene/Electrolyte Interface: Effect of Solvent on the Interfacial Capacitance

Jiang

et al. 2021

Angew Chem Int Ed

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The development of the basic understanding of the charge storage mechanisms in electrodes for energy storage applications needs deep characterization of the electrode/ electrolyte interface. In this work, we studied the charge of the double layer capacitance at single layer graphene (SLG) electrode used as a model material, in neat (EMIm-TFSI) and solvated (with acetonitrile) ionic liquid electrodes. The combination of electrochemical impedance spectroscopy and gravimetric electrochemical quartz crystal microbalance (EQCM) measurements evidence that the presence of solvent drastically increases the charge carrier density at the SLG/ionic liquid interface. The capacitance is thus governed not only by the electronic properties of the graphene, but also by the specific organization of the electrolyte side at the SLG surface originating from the strong interactions existing between the EMIm + cations and SLG surface. EQCM measurements also show that the carbon structure, with the presence of sp 2 carbons, affects the charge storage mechanism by favoring counter-ion adsorption on SLG electrode versus ion exchange mechanism in amorphous porous carbons.

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A mean-field theory on the differential capacitance of asymmetric ionic liquid electrolytes. II. Accounts of ionic interactions

Cited by 18 publications

References 13 publications

The effect of short-range interaction and correlations on the charge and electric field distribution in a model solid electrolyte

The effect of short-range interaction and correlations on the charge and electric field distribution in a model solid electrolyte

Short- and long-range contributions to equilibrium and transport properties of solid electrolytes

Electrochemical Characterization of Single Layer Graphene/Electrolyte Interface: Effect of Solvent on the Interfacial Capacitance

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