arXiv subjects

Vladislav B. Ivaništšev

Publications and source records attributed to Vladislav B. Ivaništšev.

7 recordsLinked to original sources

arXiv2026

Potential of monolayer charge

In this letter, we develop the concept of the potential of monolayer charge (PMC). Its main purpose is to serve as the fundamental reference potential for studying charged interfaces. We estimate PMC values for interfaces between Au(111) surface and frisbee-shaped ions. Density functional theory calculations suggest that increasing ion area shifts the PMC to an experimentally measurable potential range. To guide experimental verification, we have derived an analytical expression, which relates ion area, surface--ion distance, ionic charge, and the corresponding PMC value. Further exploration of the PMC can enrich interfacial electrochemistry and reveal interfacial electrophysics as an independent field.

cond-mat.mtrl-sci↗

arXiv2024

Ionic liquid-electrode interface: classification of ions, saturation of layers, and structure-determined potentials

Progress in electrochemical applications of ionic liquids builds on an understanding of electrical double-layer. This computational study focuses on structure-determined quantities -- maximum packing density, potentials and capacitances -- evaluated using a one-electrode electrical double-layer model. Interfaces of 40 studied ions are grouped into four distinct classes according to their characteristic packing at the model surface. The simulations suggest that the exact screening by a monolayer of counter-ions (preceding the crowding of ions) is unlikely for common ions within the electrochemical stability window of corresponding ionic liquids. This work discusses how the assessed structure-determined quantities can guide the experimental tuning of (electro/mechano)chemical properties and characterising the structure of ionic liquid-electrode interfaces.

cond-mat.soft↗

arXiv2022

Double layer in ionic liquids: capacitance vs. temperature from atomistic simulations

In this study, we investigated the graphene-ionic liquid (EMImBF4) interface to clarify the effects of ambient temperature and potential on the differential capacitance. We complemented molecular dynamics simulations with density functional theory calculations to unravel the electrolyte and electrode contributions to the differential capacitance. As a result, we show: (1) the relation of characteristic saddle points of the capacitance-potential curve to the structural changes; (2) the smearing effect of temperature on the local structure and, consequently, on the capacitance; (3) rationalization of these observations with the interfacial bilayer model; and, finally, (4) how quantum capacitance correction dampens the influence of temperature and improves the agreement with the experimental data. These insights are of fundamental and practical importance for the application of similar interfaces in electrochemical energy storage and transformation devices, such as capacitors and actuators.

cond-mat.mtrl-sci↗

arXiv2020

Graphene-ionic liquid interfacial potential drop from DFT-MD simulations

Ionic liquids (IL) are promising electrolytes for electrochemical applications due to their remarkable stability and high charge density. Molecular dynamics simulations are essential for better understanding the complex phenomena occurring at the electrode-IL interface. In this work, we have studied the interface between graphene and 1-ethyl-3-methyl-imidazolium tetrafluoroborate IL, using density functional theory-based molecular dynamics simulations at variable surface charge densities. We have disassembled the electrical double layer potential drop into two main components: one involving atomic charges and the other - dipoles. The latter component arises due to the electronic polarisation of the surface and is related to concepts hotly debated in the literature, such as the Thomas-Fermi screening length, effective surface charge plane, and quantum capacitance.

cond-mat.mtrl-sci↗

arXiv2017

On the thickness of the double layer in ionic liquids

In this study, we examined the thickness of the electrical double layer (EDL) in ionic liquids using density functional theory (DFT) calculations and molecular dynamics (MD) simulations. We focused on the BF4- anion adsorption from 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) ionic liquid on the Au(111) surface. At both DFT and MD levels, we evaluated the capacitance-potential dependence for the Helmholtz model of the interface. Using MD simulations, we also explored a more realistic, multilayer EDL model accounting for the ion layering. Concurrent analysis of the DFT and MD results provides a ground for thinking whether the electrical double layer in ionic liquids is one- or multi-ionic-layer thick.

cond-mat.soft↗

arXiv2017

DFT study of ionic liquids adsorption on circumcoronene shaped graphene

Carbon materials have a range of properties such as high electrical conductivity, high specific surface area, and mechanical flexibility are relevant for electrochemical applications. Carbon materials are utilised in energy conversion-and-storage devices along with electrolytes of complementary properties. In this work, we study the interaction of highly concentrated electrolytes (ionic liquids) at a model carbon surface (circumcoronene) using density functional theory methods. Our results indicate the decisive role of the dispersion interactions that noticeably strengthen the circumcoronene-ion interaction. Also, we focus on the adsorption of halide anions as the electrolytes containing these ions are promising for practical use in supercapacitors and solar cells.

cond-mat.soft↗

arXiv2016

Molecular dynamics simulation of behaviour of water in nano-confined ionic liquid--water mixtures

This work describes the behaviour of water molecules in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under nanoconfinement between graphene sheets. By means of molecular dynamics simulations, an adsorption of water molecules at the graphene surface is studied. A depletion of water molecules in the vicinity of the neutral and negatively charged graphene surfaces and their adsorption at the positively charged surface are observed in line with the preferential hydration of the ionic liquid anions. The findings are appropriately described using a two-level statistical model. The confinement effect on the structure and dynamics of the mixtures is thoroughly analyzed using the density and the potential of mean force profiles, as well as by the vibrational densities of states of water molecules near the graphene surface. The orientation of water molecules and the water-induced structural transitions in the layer closest to the graphene surface are also discussed.

cond-mat.soft↗