4.6 Article

On Capacitance Enhancement at Decreasing Pore Width and its Relation with Solvent Concentration and Polarity

Related references

Note: Only part of the references are listed.
Review Chemistry, Multidisciplinary

Theory and Simulations of Ionic Liquids in Nanoconfinement

Svyatoslav Kondrat et al.

Summary: Room-temperature ionic liquids (RTILs) have diverse applications and exhibit fascinating structural and dynamic phenomena when confined in nanostructures. This review analyzes the physical phenomena, theoretical models, and simulation approaches that study the properties of confined RTILs. The review highlights the importance of molecular simulations in providing microscopic insights and discusses the challenges and applicability of different simulation approaches.

CHEMICAL REVIEWS (2023)

Article Electrochemistry

On the key role of electrolyte-electrode van der Waals interactions in the simulation of ionic liquids-based supercapacitors

Camille Bacon et al.

Summary: The performance of supercapacitors is influenced by the structure and dynamics of ions at the solid/liquid interface, which are determined by the electrolyte-electrolyte and electrolyte-electrode interactions. This study investigates the impact of the strength of electrode-electrolyte van der Waals interactions on the interfacial properties of an ionic liquid and a graphite electrode using constant potential classical molecular dynamics. The results show that stronger van der Waals interactions lead to a decrease in ion exchange and lower capacitance of the devices, highlighting the importance of accurate parameterization of force fields for electrode materials in future studies.

ELECTROCHIMICA ACTA (2023)

Article Electrochemistry

Ion transport from water-in-salt electrolyte through porosity of hierarchical porous carbons unraveled by solid-state NMR

Gelines Moreno-Fernandez et al.

Summary: Electrical double-layer capacitors (EDLCs) have limitations in energy storage due to their high unit energy cost and low specific energy. Water-in-salt electrolytes have been proposed as a more affordable option, but their high viscosity and limited conductivity hinder their direct use in high-power devices. This study uses solid-state NMR and electrolyte-tuned porosity carbons to demonstrate the significant impact of relative pore/ion size on electrolyte propagation in the pores. The findings also explain the radical changes in electrochemical response observed using carbons with different nanosized pores and a water-in-salt electrolyte.

ELECTROCHIMICA ACTA (2022)

Article Chemistry, Multidisciplinary

Unusual properties of the electric double layer in an extremely narrow nanotube. A grand canonical Monte Carlo and classical DFT study

Shiqi Zhou et al.

Summary: The study utilized a grand canonical Monte Carlo simulation technique and classical density functional theory to investigate ion distribution and differential capacitance in extremely narrow nanotubes. Results showed systematic changes in ion distributions and differential capacitance under different electrolyte concentrations.

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS (2022)

Article Nanoscience & Nanotechnology

Origin of Enhanced Performance in Nanoporous Electrical Double Layer Capacitors: Insights on Micropore Structure and Electrolyte Composition from Molecular Simulations

Betul Uralcan et al.

Summary: This study investigates the effect of solvation and micropore structure on the energy storage performance of electrical double layer capacitors. The results show that electrodes with larger pores have faster charging profiles and the charging time depends nonmonotonically on ion concentration. When the average pore size of the electrode is similar to or slightly larger than the size of a solvated ion, solvation enhances ion electrosorption into nanopores. Additionally, the capacitance exhibits a nonmonotonic dependence on ion concentration, increasing with the introduction of solvent in the concentrated regime and decreasing with further dilution. These findings provide novel insights on the charging kinetics and equilibrium behavior of electrical double layer capacitors and can facilitate the optimization of material properties for such applications.

ACS APPLIED MATERIALS & INTERFACES (2022)

Article Chemistry, Physical

Capacitance response and concentration fluctuations close to ionic liquid-solvent demixing

Carolina Cruz et al.

Summary: This study investigates the concentration fluctuations in an electrolyte confined between electrodes formed by parallel graphene layers. The effect of proximity to the demixing transition on electric double layers is analyzed and compared to theoretical predictions. The results show that lowering temperature enhances capacitance for dilute ionic solutions near the demixing transition, while higher ionic concentrations have a less noticeable effect. Additionally, the shape of the capacitance changes, exhibiting a maximum at the potential of zero charge and symmetric maxima for positive and negative voltages.

JOURNAL OF MOLECULAR LIQUIDS (2022)

Article Chemistry, Physical

Capacitance and Structure of Electric Double Layers: Comparing Brownian Dynamics and Classical Density Functional Theory

Peter Cats et al.

Summary: The study compares expensive Brownian Dynamics simulations with classical Density Functional Theory calculations and finds excellent overall agreement for various system parameters. The study focuses on distinguishing differential capacitance at fixed number of ions and fixed ionic chemical potential, and derives and exploits their thermodynamic relations. The quantitative agreement between simulation and theory indicates the potential of DFT for accurately studying room temperature ionic liquids at lower dielectric constants than water.

JOURNAL OF SOLUTION CHEMISTRY (2022)

Article Chemistry, Physical

Capacitance of Carbon Nanotube/Graphene Composite Electrodes with [BMIM+][BF4-]/Acetonitrile: Fixed Voltage Molecular Dynamics Simulations

Jesse G. McDaniel

Summary: The capacitance of nanoporous carbon electrode materials is influenced by the interactions with electrolyte. In this study, computer simulations were used to predict structure/capacitance relationships for different model morphologies of CNT/G composite electrodes. The results indicate that CNT/graphene contact points enhance charge separation and a specific nanoconfinement motif can significantly increase local capacitance.

JOURNAL OF PHYSICAL CHEMISTRY C (2022)

Article Physics, Applied

Ultrananoporous supercapacitor with ionic liquid comprised of two-site cation: an Ising model study (II)

Shiqi Zhou et al.

Summary: The research shows that ion valence affects the saturation energy storage value and threshold voltage strength, while pore diameter significantly influences both the saturation energy storage value and differential capacitance peak height. Ion size and valence also impact the saturation energy storage value and threshold voltage strength.

JOURNAL OF PHYSICS D-APPLIED PHYSICS (2022)

Article Electrochemistry

Enhancing Cycling Stability and Specific Capacitance of Vanadium Nitride Electrodes by Tuning Electrolyte Composition

Emile Haye et al.

Summary: In this study, the researchers propose a strategy of tuning the electrolyte composition to limit the capacitance fade of vanadium nitride (VN) electrode. By adding V5+ ions to the electrolyte, the cycling stability of the VN electrode is enhanced and the capacitance fade is decreased. The presence of V5+ species in the solution stabilizes an oxide/oxynitride layer at the VN surface, leading to improved cycling stability.

JOURNAL OF THE ELECTROCHEMICAL SOCIETY (2022)

Article Electrochemistry

Exploring the chemistry of Organic/water-in-salt electrolyte in graphene-polypyrrole based high-voltage (2.4V) microsupercapacitor

Navpreet Kamboj et al.

Summary: This study successfully fabricated a metal-free microsupercapacitor with enhanced electrochemical performance by using laser-irradiated graphene-polyprrole hybrid material. The incorporation of pseudocapacitive material increased the electrochemical storage capacity of the device. Furthermore, the solvation structure of the electrolyte was analyzed to support the study.

ELECTROCHIMICA ACTA (2022)

Article Chemistry, Physical

Effective electrostatic forces between two neutral surfaces with surface charge separation: valence asymmetry and dielectric constant heterogeneity

S. Zhou

Summary: Based on CDFT calculations, this study investigates the surface electrostatic force (SEF) between two overall neutral surfaces with atomic scale strip shape charge distribution. The effects of ion valence and dielectric constant heterogeneity are analyzed, and their impact on the SEF shape and strength is discussed.

MOLECULAR PHYSICS (2022)

Article Physics, Multidisciplinary

Influence of ion structure and solvent electric dipole on ultrananoporous supercapacitor: a lattice model study

S. Zhou et al.

Summary: A five-state modified BEG model is proposed to describe the electrolyte in a cylindrical electrode pore in polar solvent. The model takes into account the dimer structure of the cation and the electric dipole of the polar solvent. The effects of ion structure, electric valence, solvent electric dipole, and pore size on specific differential capacitance and specific energy storage of a supercapacitor are investigated. The main findings are that the dimer counter-ion electric valence does not greatly impact the energy storage, but reduces the threshold electrode potential strength. The size of the dimer neutral site affects the peak height of the differential capacitance and the energy storage. Increase in solvent electric dipole moment raises the energy storage value and expands the solvent domain around zero electrode potential. Increase in pore size reduces the energy storage value and increases the electrode potential strength.

PHYSICA SCRIPTA (2022)

Article Chemistry, Physical

Mechanism of oscillation of aqueous electrical double layer capacitance: Role of solvent

S. Zhou

Summary: This study focuses on the role of solvent in the behavior of differential capacitance (Cd) in aqueous electrolyte electric double-layer capacitors (EDLCs). The findings show that increasing the electrolyte bulk concentration causes a shift in the Cd(H) curve, and there is a negative correlation between Cd and concentration at high voltage. The oscillation periods of Cd(H) curves are fixed at 3A, and considering the solvent granularity and polarity reduces the attenuation rate of the oscillation.

JOURNAL OF MOLECULAR LIQUIDS (2022)

Article Chemistry, Physical

Double layer in ionic liquids: Temperature effect and bilayer model

Heigo Ers et al.

Summary: This work investigates the influence of potential and temperature on the interfacial structure and properties of graphene-ionic liquid. The study reveals a novel phenomenon of ionic saturation and explores its implications using classical molecular dynamics simulations and quantum density functional theory calculations. The results highlight the role of quantum capacitance in mitigating the temperature effect and improving the agreement with experimental data. The findings have both fundamental and practical significance for electrochemical energy storage and transformation devices.

JOURNAL OF MOLECULAR LIQUIDS (2022)

Article Physics, Fluids & Plasmas

Structure of electrolyte solutions at nonuniformly charged surfaces on a variety of length scales

Markus Bier et al.

Summary: A unified classical density functional theory approach is used to systematically study the structures of dilute electrolyte solutions close to nonuniformly charged planar substrates across the entire spectrum of microscopic to macroscopic length scales. The study reveals that interactions with microscopic ranges have negligible influence on the formation of nonuniform lateral structures. Additionally, a coupling between the lateral and the normal fluid structures is observed, where fewer details of the lateral nonuniformities contribute to the fluid structure as the distance from the substrate increases, ultimately leaving only large-scale surface features relevant.

PHYSICAL REVIEW E (2022)

Article Physics, Multidisciplinary

Ising model study on effects of solvent electric dipole on ultrananoporous supercapacitor

Shiqi Zhou et al.

Summary: The study of a one-dimensional three-state Ising model reveals that the solvent electric dipole has a significant impact on specific differential capacitance and energy storage in cylindrical pores. High valence ions can increase saturation energy storage, while the presence of bivalent co-ions can lower the threshold surface potential strength.

CHINESE JOURNAL OF PHYSICS (2021)

Article Chemistry, Multidisciplinary

A statistical mechanics study on relationship between nanopore size and energy storage in supercapacitors

S. Zhou

Summary: The study explores the impact of cylindrical pore electrode size on differential electrical capacitance and energy storage density curves using classical density functional theory. Results indicate that symmetrical high valence electrolytes enhance energy storage density, and smaller pore sizes exhibit saturation trends under certain voltage conditions.

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS (2021)

Article Chemistry, Physical

Carbon-carbon supercapacitors: Beyond the average pore size or how electrolyte confinement and inaccessible pores affect the capacitance

El Hassane Lahrar et al.

Summary: In this study, molecular simulations were used to demonstrate that carbon electrodes with a more ordered structure and a well defined pore size exhibit higher capacitance compared to those with a more disordered structure and a broader pore size distribution. This is attributed to the larger quantities and higher confinement of ions adsorbed in the ordered carbon, which favor better charge separation. This work opens the door to computationally tractable screening strategies for supercapacitors.

JOURNAL OF CHEMICAL PHYSICS (2021)

Article Chemistry, Multidisciplinary

Impacts of solvent electric dipole and ion valency on energy storage in ultrananoporous supercapacitor: An ising model study

Shiqi Zhou et al.

Summary: A four-state BEG model was constructed to investigate the effects of solvent molecule electric dipole and ion valency on the differential capacitance Cd and energy storage E of a supercapacitor based on the electrical double layer in an ultranano cylindrical pore. The study revealed several new effects such as the presence of a zero Cd and E platform around zero surface potential, correlation between saturated surface potential and solvent transfer energy, and the increase of energy storage by enhancing the solvent electrical dipole moment.

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS (2021)

Article Chemistry, Multidisciplinary

The Influence of Anion Structure on the Ionic Liquids/Au (100) Interface by Molecular Dynamics Simulations

Yue Wang et al.

Summary: The microstructure and electronic structure of different ionic liquids lead to interesting universal laws in the electrical double layers. The morphology of anions on electrode surface varies due to geometric differences, and the energy levels are influenced by the electronegativity of central atoms. Stronger interactions between particles and electrodes result in unique patterns and thinner effective EDL, impacting the differential capacitance values.

LANGMUIR (2021)

Article Electrochemistry

Ionic liquid-metal interface: The origins of capacitance peaks

Iuliia V. Voroshylova et al.

Summary: The complexity of electrode charge screening in ionic liquids is well-known, resulting in distinctive structural changes and capacitance peaks at interfaces due to strong ion correlations. Molecular dynamics simulations have been used to study differential capacitance for various ILs with metal electrodes, highlighting the challenge of obtaining a capacitance-potential curve. This study focused on MD simulations of a specific IL at a gold surface, revealing the dependence of capacitance on the fitting method and identifying capacitance peaks and structural reorganization types.

ELECTROCHIMICA ACTA (2021)

Article Electrochemistry

A novel strategy to achieve 2V symmetric supercapacitor using B, N doped rGO as an electrode material in water in salt based hydrous electrolyte

Prakas Samanta et al.

Summary: The use of B & N-doped reduced graphene oxide as carbonaceous electrode materials and a solid-state electrolyte composed of polyethylene glycol and sodium dodecyl sulfate resulted in solid-state symmetric supercapacitors with high power density, energy density, and long cycle life.

ELECTROCHIMICA ACTA (2021)

Article Electrochemistry

Temperature dependences of the double layer capacitance of some solid/liquid and solid/solid electrified interfaces. An experimental study

Sebastian A. Watzele et al.

Summary: This study investigates the impact of temperature on the electrical double layer capacitance (CDL) of various materials relevant to fuel cells and solid-state Li-ion batteries. The results show different behaviors of CDL with temperature for different materials, which is crucial for understanding and modeling interface processes in renewable energy conversion systems.

ELECTROCHIMICA ACTA (2021)

Article Chemistry, Physical

The differential capacitance as a probe for the electric double layer structure and the electrolyte bulk composition

Peter Cats et al.

Summary: This theoretical study investigates the differential capacitance of an aqueous electrolyte in contact with a planar electrode, demonstrating that small trace amounts of divalent ions can greatly influence the differential capacitance, while small ions dominate its behavior for high electrode potentials. A new differential capacitance expression is derived from mechanical equilibrium in a planar geometry, emphasizing the importance of the first layer of ions near the charged surface for understanding. These insights can serve as a guide in experiments to better understand the electrolyte-electrode interface and the composition of the bulk electrolyte.

JOURNAL OF CHEMICAL PHYSICS (2021)

Article Chemistry, Physical

Structure-Capacitance Relationships of Graphene/Ionic Liquid Electrolyte Double Layers

Yi-Jung Tu et al.

Summary: Using constant voltage molecular dynamics simulations, we found that ionic liquids exhibit camel-shaped capacitance profiles with two peaks on either side of a minimum centered at the potential of zero charge on model graphene electrodes. The electric-field-induced rearrangement of ion structure within the inner layer closest to the electrode interface were observed, resulting in increased inner-layer charge density and higher capacitance with increasing voltage. The presence of organic solvent significantly alters the composition of the inner layer, affecting the ion/electrode contact at moderate potentials.

JOURNAL OF PHYSICAL CHEMISTRY C (2021)

Article Electrochemistry

Ionic Competition over Adsorption into Charged Spherical Cavities Affecting the Shape of Electric Double Layer Capacitance Curve and Zeta Potential: A Density Functional Theory Study

Ezat Keshavarzi et al.

Summary: The formation of the electric double layer at the concave wall of a charged spherical cavity was investigated using modified fundamental measure theory within the framework of the restricted primitive model. Results showed that the presence of even low concentrations of C (2+) can lead to a remarkable change in the shape of the capacitance curve, with concentration playing a crucial role at low electric potentials and ion charge dominating at higher potentials.

JOURNAL OF THE ELECTROCHEMICAL SOCIETY (2021)

Article Chemistry, Applied

Adsorption of light gases in covalent organic frameworks: comparison of classical density functional theory and grand canonical Monte Carlo simulations

Christopher Kessler et al.

Summary: A classical density functional theory (cDFT) based on the PC-SAFT equation of state is proposed for the calculation of adsorption equilibria in covalent organic frameworks (COFs). The results show excellent agreement between PC-SAFT DFT and GCMC simulations for adsorption isotherms in COFs, indicating the predictive power of the method in selective accumulation of longer hydrocarbons in binary mixtures.

MICROPOROUS AND MESOPOROUS MATERIALS (2021)

Article Physics, Condensed Matter

Ising models of charge storage in multifile metallic nanopores

A. O. Zaboronsky et al.

JOURNAL OF PHYSICS-CONDENSED MATTER (2020)

Article Chemistry, Physical

Heterogeneous surface charge confining an electrolyte solution

Maximilian Mussotter et al.

JOURNAL OF CHEMICAL PHYSICS (2020)

Article Chemistry, Physical

Diffusivity and Structure of Room Temperature Ionic Liquid in Various Organic Solvents

Jinlei Cui et al.

JOURNAL OF PHYSICAL CHEMISTRY B (2020)

Article Physics, Fluids & Plasmas

Toward a density-functional theory for the Jagla fluid

Florian Gussmann et al.

PHYSICAL REVIEW E (2020)

Article Computer Science, Interdisciplinary Applications

Incorporating surface polarization effects into large-scale coarse-grained Molecular Dynamics simulation

Trung Dac Nguyen et al.

COMPUTER PHYSICS COMMUNICATIONS (2019)

Article Mechanics

Differential capacitance of uniformly charged hard-sphere ions in planar electric double layers

Minhye Heo et al.

JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT (2019)

Article Nanoscience & Nanotechnology

Effects of Solvent Concentration on the Performance of Ionic-Liquid/Carbon Supercapacitors

Yu Zhang et al.

ACS APPLIED MATERIALS & INTERFACES (2019)

Article Computer Science, Interdisciplinary Applications

A parallel electrostatic Particle-in-Cell method on unstructured tetrahedral grids for large-scale bounded collisionless plasma simulations

Sergey N. Averkin et al.

JOURNAL OF COMPUTATIONAL PHYSICS (2018)

Article Chemistry, Physical

Capacitance Optimization in Nanoscale Electrochemical Supercapacitors

Srinivasa Rao Varanasi et al.

JOURNAL OF PHYSICAL CHEMISTRY C (2015)

Article Chemistry, Physical

Electrode Models for Ionic Liquid-Based Capacitors

Konrad Breitsprecher et al.

JOURNAL OF PHYSICAL CHEMISTRY C (2015)

Article Chemistry, Physical

First-Principles-Inspired Design Strategies for Graphene-Based Supercapacitor Electrodes

Brandon C. Wood et al.

JOURNAL OF PHYSICAL CHEMISTRY C (2014)

Article Chemistry, Physical

Oscillations in the capacitance of a nanopore containing an electrolyte due to pore width and nonzero size ions

Douglas Henderson

JOURNAL OF COLLOID AND INTERFACE SCIENCE (2012)

Article Chemistry, Physical

Solvent Effect on the Pore-Size Dependence of an Organic Electrolyte Supercapacitor

De-en Jiang et al.

JOURNAL OF PHYSICAL CHEMISTRY LETTERS (2012)

Article Chemistry, Physical

Supercapacitor Capacitance Exhibits Oscillatory Behavior as a Function of Nanopore Size

Guang Feng et al.

JOURNAL OF PHYSICAL CHEMISTRY LETTERS (2011)

Article Chemistry, Multidisciplinary

Oscillation of Capacitance inside Nanopores

De-en Jiang et al.

NANO LETTERS (2011)

Article Chemistry, Physical

Capacitance in carbon pores of 0.7 to 15 nm: a regular pattern

Teresa A. Centeno et al.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS (2011)

Article Chemistry, Physical

Differential Capacitance of Room Temperature Ionic Liquids: The Role of Dispersion Forces

Martin Trulsson et al.

JOURNAL OF PHYSICAL CHEMISTRY LETTERS (2010)

Article Electrochemistry

EDLC performance of carbide-derived carbons in aprotic and acidic electrolytes

J. A. Fernandez et al.

ELECTROCHIMICA ACTA (2008)

Article Computer Science, Interdisciplinary Applications

New-version-fast-multipole-method accelerated electrostatic calculations in biomolecular systems

Benzhuo Lu et al.

JOURNAL OF COMPUTATIONAL PHYSICS (2007)