Electric double layer theory for room temperature ionic liquids on charged electrodes: Milestones and prospects

Budkov, Yu. A.; Kolesnikov, A. L.

doi:10.1016/j.coelec.2021.100931

Cited by 20 publications

(16 citation statements)

References 60 publications

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“…All of the above phenomena are already known from classical GCS models ,− and in our previous works. , The use of a Morse potential that is deeper and closer to the metal surface for water results in a dense packing of water molecules on the metal surface, Figure g. Hydrated counterions reside outside of this water layer; see a schematic diagram in Figure i.…”

Section: Model Parameterization and Calibrationmentioning

confidence: 64%

“…The camel–volcano transition has been clearly exposited by Kornyshev, 48 and many others; see a recent review. 49 However, these classical EDL models would predict the volcano peak is also at the pzc where the camel minima are located. By contrast, the present model shows a left shift of the volcano peak relative to the pzc, which is a manifestation of metal electronic effects.…”

Section: Parametric Analysismentioning

confidence: 98%

“…The camel shape with the minima at the pzc is transitioned to a volcano shape when the ion concentration increases. The camel–volcano transition has been clearly exposited by Kornyshev, and many others; see a recent review . However, these classical EDL models would predict the volcano peak is also at the pzc where the camel minima are located.…”

Section: Parametric Analysismentioning

confidence: 99%

“…Specifically, the radius of hydrated K + and PF 6 – are 5 and 4 Å, respectively. According to classical EDL models, ,− the size asymmetry will lead to asymmetric camel shapes. For the present case, one would expect that the peak at lower electrode potential that signifies crowding of larger cations would be smaller than that at more positive electrode potential.…”

Section: Parametric Analysismentioning

confidence: 99%

See 3 more Smart Citations

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF₆ System and Parametric Analysis

Huang

2023

J. Chem. Theory Comput.

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The density-potential functional theory (DPFT) of electrochemical double layer (EDL) is upgraded by adopting (generalized) gradient approximations for kinetic, exchange, and correlation functionals of metal electrons. A new numerical scheme that is more stable and converges faster is proposed to solve the DPFT model. The DPFT model is calibrated with existing differential double-layer capacitance (C dl) data of the EDL at Ag(111)-KPF6 aqueous interface at five concentrations at room temperature. Metal electronic effects are essential to explain why the two peaks of the camel-shaped C dl curves are almost symmetric in spite of the size difference of the hydrated cations and anions. A systematic parametric analysis is then conducted in terms of key EDL properties, including the potential of zero charge and the differential capacitance. The parametric analysis, on the one hand, elucidates how quantum mechanical behaviors of metal electrons as well as interactions between metal electrons and the electrolyte solution impact the EDL properties and, on the other hand, identifies key parameters of the DPFT model, which should be calibrated using first-principles calculations and/or advanced experiments in the future.

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Section: Model Parameterization and Calibrationmentioning

confidence: 64%

Section: Parametric Analysismentioning

confidence: 98%

Section: Parametric Analysismentioning

confidence: 99%

Section: Parametric Analysismentioning

confidence: 99%

See 2 more Smart Citations

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF₆ System and Parametric Analysis

Huang

2023

J. Chem. Theory Comput.

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“…The two peaks usually signify overcrowding of counterions near the metal surface, which are usually asymmetric due to different sizes of cations and anions. The two peaks move closer and eventually melt into a single peak as the electrolyte solution gets more and more concentrated. , …”

Section: Introductionmentioning

confidence: 99%

Zooming into the Inner Helmholtz Plane of Pt(111)–Aqueous Solution Interfaces: Chemisorbed Water and Partially Charged Ions

Huang

2023

JACS Au

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The double layer on transition metals, i.e., platinum, features chemical metal–solvent interactions and partially charged chemisorbed ions. Chemically adsorbed solvent molecules and ions are situated closer to the metal surface than electrostatically adsorbed ions. This effect is described tersely by the concept of an inner Helmholtz plane (IHP) in classical double layer models. The IHP concept is extended here in three aspects. First, a refined statistical treatment of solvent (water) molecules considers a continuous spectrum of orientational polarizable states, rather than a few representative states, and non-electrostatic, chemical metal–solvent interactions. Second, chemisorbed ions are partially charged, rather than being electroneutral or having integral charges as in the solution bulk, with the coverage determined by a generalized, energetically distributed adsorption isotherm. The surface dipole moment induced by partially charged, chemisorbed ions is considered. Third, considering different locations and properties of chemisorbed ions and solvent molecules, the IHP is divided into two planes, namely, an AIP (adsorbed ion plane) and ASP (adsorbed solvent plane). The model is used to study how the partially charged AIP and polarizable ASP lead to intriguing double-layer capacitance curves that are different from what the conventional Gouy–Chapman–Stern model describes. The model provides an alternative interpretation for recent capacitance data of Pt(111)–aqueous solution interfaces calculated from cyclic voltammetry. This revisit brings forth questions regarding the existence of a pure double-layer region at realistic Pt(111). The implications, limitations, and possible experimental confirmation of the present model are discussed.

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Understanding the Electric Double Layer at the Electrode‐Electrolyte Interface: Part I – No Ion Specific Adsorption

Mazur,

Brandyshev,

Doronin

et al. 2024

ChemPhysChem

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We present a comprehensive mean‐field model that takes into account the key components of modern electrical double layer theory at the interface between an electrode and an electrolyte solution. The model considers short‐range specific interactions between different species, including electrode‐ion repulsion, the hydration of ions, dielectric saturation of solvent (water), and excluded volume (steric) interactions between species. By solving a modified Poisson‐Boltzmann equation and using the appropriate results of quantum chemistry calculations on the hydration of ions, we can accurately approximate the differential capacitance profiles of aqueous electrolyte solutions at the boundary with a silver electrode. The specific interactions between the ions and the electrodes in the systems under consideration are assumed to be significantly weaker than their Coulomb interactions. A novel aspect of our research is the investigation of the impact of short‐range ion‐water interactions on the differential capacitance, which provides new insights into the behavior of the electrical double layer. This model holds the potential to be useful for electrochemical engineers working on the development of supercapacitors and related electrochemical energy storage devices. It serves as a basis for future modeling of electrolyte systems on real electrodes, especially in scenarios where chemical ion‐electrode interactions are significant.

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Electric double layer theory for room temperature ionic liquids on charged electrodes: Milestones and prospects

Cited by 20 publications

References 60 publications

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF₆ System and Parametric Analysis

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF₆ System and Parametric Analysis

Zooming into the Inner Helmholtz Plane of Pt(111)–Aqueous Solution Interfaces: Chemisorbed Water and Partially Charged Ions

Understanding the Electric Double Layer at the Electrode‐Electrolyte Interface: Part I – No Ion Specific Adsorption

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Electric double layer theory for room temperature ionic liquids on charged electrodes: Milestones and prospects

Cited by 20 publications

References 60 publications

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF6 System and Parametric Analysis

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF6 System and Parametric Analysis

Zooming into the Inner Helmholtz Plane of Pt(111)–Aqueous Solution Interfaces: Chemisorbed Water and Partially Charged Ions

Understanding the Electric Double Layer at the Electrode‐Electrolyte Interface: Part I – No Ion Specific Adsorption

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Product

Resources

About

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF₆ System and Parametric Analysis

Density-Potential Functional Theory of Electrochemical Double Layers: Calibration on the Ag(111)-KPF₆ System and Parametric Analysis