1
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Gaudy N, Salanne M, Merlet C. Dynamics and Energetics of Ion Adsorption at the Interface between a Pure Ionic Liquid and Carbon Electrodes. J Phys Chem B 2024; 128:5064-5071. [PMID: 38738820 DOI: 10.1021/acs.jpcb.4c01192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Molecular dynamics simulations have been used extensively to determine equilibrium properties of the electrode-electrolyte interface in supercapacitors held at various potentials. While such studies are essential to understand and optimize the performance of such energy storage systems, investigation of the dynamics of adsorption during the charge of the supercapacitors is also necessary. Dynamical properties are especially important to get an insight into the power density of supercapacitors, one of their main assets. In this work, we propose a new method to coarse-grain simulations of all-atom systems and compute effective Lennard-Jones and Coulomb parameters, allowing subsequently to analyze the trajectories of adsorbing ions. We focus on pure 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide in contact with planar carbon electrodes. We characterize the evolution of the ion orientation and ion-electrode distance during adsorption and show that ions reorientate as they adsorb. We then determine the forces experienced by the adsorbing ions and demonstrate that Coulomb forces are dominant at a long range while van der Waals forces are dominant at a short range. We also show that there is an almost equal contribution from the two forces at an intermediate distance, explaining the peak of ion density close to the electrode surface.
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Affiliation(s)
- Nicolas Gaudy
- CIRIMAT, Université de Toulouse, CNRS, Université Toulouse 3 - Paul Sabatier, 118 Route de Narbonne, 31062 cedex 9 Toulouse, France
- Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), Fédération de Recherche CNRS 3459, HUB de l'Énergie, Rue Baudelocque, 80039 Amiens, France
| | - Mathieu Salanne
- Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, F-75005 Paris, France
- Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), Fédération de Recherche CNRS 3459, HUB de l'Énergie, Rue Baudelocque, 80039 Amiens, France
| | - Céline Merlet
- CIRIMAT, Université de Toulouse, CNRS, Université Toulouse 3 - Paul Sabatier, 118 Route de Narbonne, 31062 cedex 9 Toulouse, France
- Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), Fédération de Recherche CNRS 3459, HUB de l'Énergie, Rue Baudelocque, 80039 Amiens, France
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2
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Yang J, Papaderakis AA, Roh JS, Keerthi A, Adams RW, Bissett MA, Radha B, Dryfe RAW. Measuring the Capacitance of Carbon in Ionic Liquids: From Graphite to Graphene. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:3674-3684. [PMID: 38476828 PMCID: PMC10926162 DOI: 10.1021/acs.jpcc.3c08269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 03/14/2024]
Abstract
The physical electrochemistry of the carbon/ionic liquids interface underpins the processes occurring in a vast range of applications spanning electrochemical energy storage, iontronic devices, and lubrication. Elucidating the charge storage mechanisms at the carbon/electrolyte interface will lead to a better understanding of the operational principles of such systems. Herein, we probe the charge stored at the electrochemical double layer formed between model carbon systems, ranging from single-layer graphene to graphite and the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI). The effect of the number of graphene layers on the overall capacitance of the interface is investigated. We demonstrate that in pure EMIM-TFSI and at moderate potential biases, the electronic properties of graphene and graphite govern the overall capacitance of the interface, while the electrolyte contribution to the latter is less significant. In mixtures of EMIM-TFSI with solvents of varying relative permittivity, the complex interplay between electrolyte ions and solvent molecules is shown to influence the charge stored at the interface, which under certain conditions overcomes the effects of relative permittivity. This work provides additional experimental insights into the continuously advancing topic of electrochemical double-layer structure at the interface between room temperature ionic liquids and carbon materials.
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Affiliation(s)
- Jing Yang
- Department
of Chemistry and Henry Royce Institute, The University of Manchester, Oxford Road, M13
9PL Manchester, U.K.
| | - Athanasios A. Papaderakis
- Department
of Chemistry and Henry Royce Institute, The University of Manchester, Oxford Road, M13
9PL Manchester, U.K.
| | - Ji Soo Roh
- Department
of Materials, The University of Manchester, Oxford Road, M13 9PL Manchester, U.K.
- National
Graphene Institute, The University of Manchester, Oxford Road, M13 9PL Manchester, U.K.
| | - Ashok Keerthi
- Department
of Chemistry and Henry Royce Institute, The University of Manchester, Oxford Road, M13
9PL Manchester, U.K.
- National
Graphene Institute, The University of Manchester, Oxford Road, M13 9PL Manchester, U.K.
| | - Ralph W. Adams
- Department
of Chemistry and Henry Royce Institute, The University of Manchester, Oxford Road, M13
9PL Manchester, U.K.
| | - Mark A. Bissett
- Department
of Materials, The University of Manchester, Oxford Road, M13 9PL Manchester, U.K.
- National
Graphene Institute, The University of Manchester, Oxford Road, M13 9PL Manchester, U.K.
| | - Boya Radha
- Department
of Physics and Astronomy, The University
of Manchester, Oxford
Road, M13 9PL Manchester, U.K.
| | - Robert A. W. Dryfe
- Department
of Chemistry and Henry Royce Institute, The University of Manchester, Oxford Road, M13
9PL Manchester, U.K.
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3
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Ntim S, Sulpizi M. Differential Capacitance of Ionic Liquid Confined between Metallic Interfaces. J Phys Chem B 2024; 128:1936-1942. [PMID: 38378468 DOI: 10.1021/acs.jpcb.3c08042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
We present here a detailed analysis of the electric double layer at the gold electrode/[BMIM][BF4] interface using a polarizable model for the electrode, based on our recent approach to include image charges [Geada et al. Nat. Commun. 2018, 9, 716]. A double bell (camel) shape is obtained for the differential capacitance, where the inclusion of metal polarization allows for a higher density of ions in the double layer, particularly around the maxima, thereby increasing the capacitance. The charging mechanism differs for the positive and negative electrodes, with counterion adsorption prevailing at the anode and co-ion desorption prevailing at the cathode. The charging mechanism is predominantly governed by the BF4 anions, serving as counterions and co-ions at the anode and cathode, respectively. Within the considered range of potentials, only minor changes are observed in the dynamical properties, specifically in the diffusion coefficients. Notably, it is interesting to observe that bulk properties are restored at a shorter distance from the gold surface in the case of the anode compared to the cathode.
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Affiliation(s)
- Samuel Ntim
- Insitut für Physik, Johannes Gutenber Universität, Staudingerweg 7, Mainz 55128, Germany
| | - Marialore Sulpizi
- Insitut für Physik, Ruhr Universität Bochum, Universitätstrasse 150, Bochum 44801, Germany
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4
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Prakash K, Sathian SP. Temperature-dependent differential capacitance of an ionic liquid-graphene-based supercapacitor. Phys Chem Chem Phys 2024; 26:4657-4667. [PMID: 38251719 DOI: 10.1039/d3cp05039d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
One of the critical factors affecting the performance of supercapacitors is thermal management. The design of supercapacitors that operate across a broad temperature range and at high charge/discharge rates necessitates understanding the correlation of the molecular characteristics of the device (such as interfacial structure and inter-ionic and ion-electrode interactions) with its macroscopic properties. In this study, we use molecular dynamics (MD) simulations to investigate the influence of Joule heating on the structure and dynamics of the ionic liquid (IL)/graphite-based supercapacitors. The temperature-dependent electrical double layer (EDL) and differential capacitance-potential (CD-V) curves of two different ([Bmim][BF4] and [Bmim][PF6]) IL-graphene pairs were studied under various thermal gradients. For the [Bmim][BF4] system, the differential capacitance curves transition from 'U' to bell shape under an applied thermal gradient (∇T) in the range from 3.3 K nm-1 to 16.7 K nm-1. Whereas in [Bmim][PF6], we find a positive dependence of differential capacitance with ∇T with a U-shaped CD-V curve. We examine changes in the EDL structure and screening potential (ϕ(z)) as a function of ∇T and correlate them with the trends observed in the CD-V curve. The identified correlation between the interfacial charge density and differential capacitance with thermal gradient would be helpful for the molecular design of the IL-electrode interface in supercapacitors or other chemical engineering applications.
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Affiliation(s)
- Kiran Prakash
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras, Chennai-600036, Tamil Nadu, India.
| | - Sarith P Sathian
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras, Chennai-600036, Tamil Nadu, India.
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5
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Chen Y, Wippermann K, Rodenbücher C, Suo Y, Korte C. Impedance Analysis of Capacitive and Faradaic Processes in the Pt/[Dema][TfO] Interface. ACS APPLIED MATERIALS & INTERFACES 2024; 16:5278-5285. [PMID: 38247120 PMCID: PMC10835653 DOI: 10.1021/acsami.3c15465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
The electrochemical reaction kinetics, especially the oxygen reduction reaction (ORR) at the cathode, is crucial for the performance of a fuel cell. In this study, the electrochemical processes on a polycrystalline Pt electrode in the presence of protic ionic liquid (PIL) electrolyte diethylmethylammonium triflate [Dema][TfO] are investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy. Since water is continually produced during fuel cell operation, the effect of the water content in the PIL has been intensively analyzed. In order to reveal the dependence of the interfacial reaction characteristics on the electrode potential, the impedance spectra were simulated by an equivalent circuit whose parameters can be related to both Faradaic and capacitive processes. Two interfacial resistances were identified, which differ by about 3 orders of magnitude. The larger one is a charge transfer resistance that can be associated with slow Faradaic processes like the ORR and platinum oxidation/oxide reduction. The smaller resistance is probably linked with fast processes that involve water molecules, such as hydrogen deposition and oxidation. The high- and midfrequency capacitive processes are attributed to "classical" double layer and pseudocapacitive behavior, similar to those identified under nitrogen atmosphere.
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Affiliation(s)
- Yingzhen Chen
- Institute of Energy and Climate Research─Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- RWTH Aachen University, 52062 Aachen, Germany
| | - Klaus Wippermann
- Institute of Energy and Climate Research─Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Christian Rodenbücher
- Institute of Energy and Climate Research─Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Yanpeng Suo
- Institute of Energy and Climate Research─Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- RWTH Aachen University, 52062 Aachen, Germany
| | - Carsten Korte
- Institute of Energy and Climate Research─Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- RWTH Aachen University, 52062 Aachen, Germany
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6
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Zhang K, Zhou G, Fang T, Ding Z, Liu X. The ionic liquid-based electrolytes during their charging process: Movable endpoints of overscreening effect near the electrode interface. J Colloid Interface Sci 2023; 650:648-658. [PMID: 37437444 DOI: 10.1016/j.jcis.2023.06.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 07/14/2023]
Abstract
HYPOTHESIS Adding solvents to ionic liquids (ILs) can lead to the suppression of the overscreening effect near an electrode interface. Also, this suppression can be observed in neat ILs by elongating the length of the nonpolar chains on their ions. Most neat ILs, unlike the ideal model, do not exhibit a crowding effect in experiments. Through molecular dynamics (MD) simulations, researchers can model and analyze these systems in order to understand them. SIMULATIONS In this study, the dynamic change near the electrode interface of ILs-based electrolytes was investigated using MD simulations. The phenomena observed in MD simulations are generally understandable because factors can attenuate charge densities calculated from these simulations. FINDINGS The study findings reveal that both the solvents or nonpolar chains contributed to the formation of nonpolar domains. Also, the microscopic mechanisms and influences of these nonpolar domains were clearly identified. The results are important for real life applications. Some ions form a "point to surface" layer near the electrode of neat ILs. When ILs contain long nonpolar chains, they can suppress the crowding effect through self-assembly behavior. However, when they do not have any chains or short nonpolar chains, it can be difficult to stop the overscreening effect. This means it can become challenging to begin the next stage of the crowding effect.
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Affiliation(s)
- Kun Zhang
- School of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, Shandong, China; College of Materials Science and Engineering, Qingdao University, Qingdao 266071, Shandong, China
| | - Guohui Zhou
- School of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, Shandong, China.
| | - Timing Fang
- School of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, Shandong, China
| | - Zhezheng Ding
- School of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, Shandong, China
| | - Xiaomin Liu
- School of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, Shandong, China; College of Materials Science and Engineering, Qingdao University, Qingdao 266071, Shandong, China.
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7
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Ntim S, Sulpizi M. Molecular dynamics simulations of electrified interfaces including the metal polarisation. Phys Chem Chem Phys 2023; 25:22619-22625. [PMID: 37555300 DOI: 10.1039/d3cp01472j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Understanding electrified interfaces requires an accurate description of the electric double layer which also takes into account the metal polarisation. Here we present a simple approach to the molecular dynamics simulation of electrified interfaces which combines fixed charges and a core-shell model for the description of the polarisable electron density on the metal electrode. The approach has been applied to the Au(111) surface in contact with a NaCl aqueous electrolyte solution in order to calculate the differential capacitance and to gain a detailed picture of the charging mechanism. Metal polarisation enhances the interfacial capacitance with a difference between the cathode and anode. In particular, we find that the influence of the metal polarisation on the electric double layer depends on the ion's solvation shell structure and, for the investigated interface, is more important at the cathode, where it modifies the sodium ion distribution.
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Affiliation(s)
- Samuel Ntim
- Institut für Physik, Johannes Gutenberg Universität, Staudingerweg 7, 55128-Mainz, Germany
| | - Marialore Sulpizi
- Institut für Physik, Ruhr Universität Bochum, Universitätstrasse 150, 44801 Bochum, Germany.
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8
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Zheng Q, Goodwin ZAH, Gopalakrishnan V, Hoane AG, Han M, Zhang R, Hawthorne N, Batteas JD, Gewirth AA, Espinosa-Marzal RM. Water in the Electrical Double Layer of Ionic Liquids on Graphene. ACS NANO 2023; 17:9347-9360. [PMID: 37163519 DOI: 10.1021/acsnano.3c01043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The performance of electrochemical devices using ionic liquids (ILs) as electrolytes can be impaired by water uptake. This work investigates the influence of water on the behavior of hydrophilic and hydrophobic ILs─with ethylsulfate and tris(perfluoroalkyl)trifluorophosphate or bis(trifluoromethyl sulfonyl)imide (TFSI) anions, respectively─on electrified graphene, a promising electrode material. The results show that water uptake slightly reduces the IL electrochemical stability and significantly influences graphene's potential of zero charge, which is justified by the extent of anion depletion from the surface. Experiments confirm the dominant contribution of graphene's quantum capacitance (CQ) to the total interfacial capacitance (Cint) near the PZC, as expected from theory. Combining theory and experiments reveals that the hydrophilic IL efficiently screens surface charge and exhibits the largest double layer capacitance (CIL ∼ 80 μF cm-2), so that CQ governs the charge stored. The hydrophobic ILs are less efficient in charge screening and thus exhibit a smaller capacitance (CIL ∼ 6-9 μF cm-2), which governs Cint already at small potentials. An increase in the total interfacial capacitance is observed at positive voltages for humid TFSI-ILs relative to dry ones, consistent with the presence of a satellite peak. Short-range surface forces reveal the change of the interfacial layering with potential and water uptake owing to reorientation of counterions, counterion binding, co-ion repulsion, and water enrichment. These results are consistent with the charge being mainly stored in a ∼2 nm-thick double layer, which implies that ILs behave as highly concentrated electrolytes. This knowledge will advance the design of IL-graphene-based electrochemical devices.
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Affiliation(s)
- Qianlu Zheng
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Zachary A H Goodwin
- Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom
- John A. Paulson School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Varun Gopalakrishnan
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Alexis G Hoane
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Mengwei Han
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ruixian Zhang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Nathaniel Hawthorne
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - James D Batteas
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Andrew A Gewirth
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Rosa M Espinosa-Marzal
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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9
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Khlyupin A, Nesterova I, Gerke K. Molecular scale roughness effects on electric double layer structure in asymmetric ionic liquids. Electrochim Acta 2023. [DOI: 10.1016/j.electacta.2023.142261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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10
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Wang T, Li L, Zhang F, Dai Z, Shah FU, Wang W, Xu F, An R. Microstructural probing of phosphonium-based ionic liquids on a gold electrode using colloid probe AFM. Phys Chem Chem Phys 2022; 24:25411-25419. [PMID: 36250344 DOI: 10.1039/d2cp02489f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Atomic force microscopy (AFM) with a gold colloid probe modeled as the electrode surface is employed to directly capture the contact resonance frequency of two phosphonium-based ionic liquids (ILs) containing a common anion [BScB]- and differently lengthened cations ([P6,6,6,14]+ and [P4,4,4,8]+). The comparative interfacial studies are performed by creating IL films on the surface of gold, followed by measuring the wettability, thickness of the films, adhesion forces, surface morphology and AFM-probed contact resonance frequency. In addition, the cyclic voltammetry and impedance spectroscopy measurements of the neat ILs are measured on the surface of the gold electrode. The IL with longer cation alkyl chains exhibits a well-defined thin film on the electrode surface and enhanced the capacitance than the shorter chain IL. The AFM contact resonance frequency and force curves reveal that the longer IL prefers to form stiffer ion layers at the gold electrode surface, suggesting the "…anion-anion-cation-cation…" bilayer structure, in contrast, the shorter-chain IL forms the softer cation-anion alternating structure, i.e., "…anion-cation-anion-cation…".
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Affiliation(s)
- Tiantian Wang
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Licheng Li
- Innovation Research Center of Lignocellulosic Functional Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China
| | - Fan Zhang
- Department of Engineering and Design, School of Engineering and Information, University of Sussex, Brighton, BN1 9RH, UK
| | - Zhongyang Dai
- High Performance Computing Department, National Supercomputing Center in Shenzhen, Shenzhen, 518055, China
| | - Faiz Ullah Shah
- Chemistry of Interfaces, Luleå University of Technology, 97187, Luleå, Sweden
| | - Wen Wang
- Zhongnong Guoke Planning and Design Co., Ltd, Nanjing, 210014, China
| | - Feng Xu
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Rong An
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing, 210094, China.
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11
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Gan Z, Wang Y, Lu Y, Qin J, Nie Y, He H. Insight into the camel‐to‐bell transition of differential capacitance in ionic liquids‐based supercapacitor. ChemElectroChem 2022. [DOI: 10.1002/celc.202200274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Zhongdong Gan
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Yanlei Wang
- Institute of Process Engineering Chinese Academy of Sciences Ionic LIquid and Clean Process Beiertiao #1,Zhongguancun, Haidian District 100190 Beijing CHINA
| | - Yumiao Lu
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Jingyu Qin
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Yi Nie
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
| | - Hongyan He
- Institute of Process Engineering Chinese Academy of Sciences Ionic liquid department CHINA
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12
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Jeanmairet G, Rotenberg B, Salanne M. Microscopic Simulations of Electrochemical Double-Layer Capacitors. Chem Rev 2022; 122:10860-10898. [PMID: 35389636 PMCID: PMC9227719 DOI: 10.1021/acs.chemrev.1c00925] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
Electrochemical double-layer
capacitors (EDLCs) are devices allowing
the storage or production of electricity. They function through the
adsorption of ions from an electrolyte on high-surface-area electrodes
and are characterized by short charging/discharging times and long
cycle-life compared to batteries. Microscopic simulations are now
widely used to characterize the structural, dynamical, and adsorption
properties of these devices, complementing electrochemical experiments
and in situ spectroscopic analyses. In this review,
we discuss the main families of simulation methods that have been
developed and their application to the main family of EDLCs, which
include nanoporous carbon electrodes. We focus on the adsorption of
organic ions for electricity storage applications as well as aqueous
systems in the context of blue energy harvesting and desalination.
We finally provide perspectives for further improvement of the predictive
power of simulations, in particular for future devices with complex
electrode compositions.
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Affiliation(s)
- Guillaume Jeanmairet
- Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France.,Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, 80039 Amiens, France
| | - Benjamin Rotenberg
- Sorbonne Université, CNRS, Physico-chimie des Electrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France.,Réseau sur le Stockage Électrochimique de l'Énergie (RS2E), FR CNRS 3459, 80039 Amiens, France
| | - Mathieu Salanne
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, 80039 Amiens, France.,Sorbonne Université, CNRS, Physico-chimie des Electrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France.,Institut Universitaire de France (IUF), 75231 Paris Cedex 05, France
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13
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Ratschmeier B, Braunschweig B. Role of imidazolium cations on the interfacial structure of room‐temperature ionic liquids in contact with Pt(111) electrodes. ELECTROCHEMICAL SCIENCE ADVANCES 2022. [DOI: 10.1002/elsa.202100173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- Björn Ratschmeier
- Institute of Physical Chemistry Westfälische Wilhelms‐Universität Münster Münster Germany
| | - Björn Braunschweig
- Institute of Physical Chemistry Westfälische Wilhelms‐Universität Münster Münster Germany
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14
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Qing L, Jiang J. Double-Edged Sword of Ion-Size Asymmetry in Energy Storage of Supercapacitors. J Phys Chem Lett 2022; 13:1438-1445. [PMID: 35129327 DOI: 10.1021/acs.jpclett.1c03900] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The advanced supercapacitor is of great significance for renewable energy storage. Achieving its high energy and high power densities remains a huge challenge. Herein, the contribution of ion-size asymmetry to the charging behavior of a supercapacitor is systematically studied using time-dependent density functional theory (TDDFT). We track the time evolution of the ionic microstructure inside the porous electrode and its reservoir and reveal a kinetic charge inversion in the asymmetrical ion-size cases. Compared with the symmetrical ion-size case, we find that the ion-size asymmetry has a double-edged sword effect on the energy storage of a supercapacitor: it accelerates the charging process yet reduces the differential capacitance. Additionally, the energy density and power density can simultaneously increase in the asymmetrical cases, which provides important insights toward the experimental design of supercapacitors with high energy and high power densities.
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Affiliation(s)
- Leying Qing
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Jian Jiang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
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15
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Shin SJ, Kim DH, Bae G, Ringe S, Choi H, Lim HK, Choi CH, Kim H. On the importance of the electric double layer structure in aqueous electrocatalysis. Nat Commun 2022; 13:174. [PMID: 35013347 PMCID: PMC8748683 DOI: 10.1038/s41467-021-27909-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/07/2021] [Indexed: 11/09/2022] Open
Abstract
To design electrochemical interfaces for efficient electric-chemical energy interconversion, it is critical to reveal the electric double layer (EDL) structure and relate it with electrochemical activity; nonetheless, this has been a long-standing challenge. Of particular, no molecular-level theories have fully explained the characteristic two peaks arising in the potential-dependence of the EDL capacitance, which is sensitively dependent on the EDL structure. We herein demonstrate that our first-principles-based molecular simulation reproduces the experimental capacitance peaks. The origin of two peaks emerging at anodic and cathodic potentials is unveiled to be an electrosorption of ions and a structural phase transition, respectively. We further find a cation complexation gradually modifies the EDL structure and the field strength, which linearly scales the carbon dioxide reduction activity. This study deciphers the complex structural response of the EDL and highlights its catalytic importance, which bridges the mechanistic gap between the EDL structure and electrocatalysis.
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Affiliation(s)
- Seung-Jae Shin
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Dong Hyun Kim
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Geunsu Bae
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Stefan Ringe
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, Republic of Korea.,Energy Science and Engineering Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Hansol Choi
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Hyung-Kyu Lim
- Division of Chemical Engineering and Bioengineering, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Chang Hyuck Choi
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea.
| | - Hyungjun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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16
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Pitawela N, Shaw SK. Imidazolium Triflate Ionic Liquids' Capacitance-Potential Relationships and Transport Properties Affected by Cation Chain Lengths. ACS MEASUREMENT SCIENCE AU 2021; 1:117-130. [PMID: 36785553 PMCID: PMC9885949 DOI: 10.1021/acsmeasuresciau.1c00015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper we report the effects of five imidazolium cations with varying alkyl chain lengths to study the effects of cation size on capacitance versus voltage behavior. The cations include ethyl-, butyl-, hexyl-, octyl-, and decyl-3-methylimidazolium, all paired with a triflate anion. We analyze the capacitance with respect to the cation alkyl chain length qualitatively and quantitatively by analyzing changes in the capacitance-potential curvature shape and magnitude across several standard scanning protocols and electrochemical techniques. Further, three transport properties (viscosity, diffusion coefficient, and electrical conductivity) are experimentally determined and integrated into the outcomes. Ultimately, we find higher viscosities, lower diffusion coefficients, and lower electrical conductivities when the alkyl chain length is increased. Also, capacitance values increase with cation size, except 1-octyl-3-methylimidazolium, which does not follow an otherwise linear trend. This capacitive increase is most pronounced when sweeping the potential in the cathodic direction. These findings challenge the conventional hypothesis that increasing the length of the alkyl chain of imidazolium cations diminishes the capacitance and ionic liquid performance in charge storage.
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17
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Ers H, Nerut J, Lust E, Pikma P. Long-term stability of Cd(0001) single crystal | ionic liquid interface – The effect of I− addition. J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2021.115826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Belotti M, Lyu X, Xu L, Halat P, Darwish N, Silvester DS, Goh C, Izgorodina EI, Coote ML, Ciampi S. Experimental Evidence of Long-Lived Electric Fields of Ionic Liquid Bilayers. J Am Chem Soc 2021; 143:17431-17440. [PMID: 34657417 DOI: 10.1021/jacs.1c06385] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Herein we demonstrate that ionic liquids can form long-lived double layers, generating electric fields detectable by straightforward open circuit potential (OCP) measurements. In imidazolium-based ionic liquids an external negative voltage pulse leads to an exceedingly stable near-surface dipolar layer, whose field manifests as long-lived (∼1-100 h) discrete plateaus in OCP versus time traces. These plateaus occur within an ionic liquid-specific and sharp potential window, defining a simple experimental method to probe the onset of interfacial ordering phenomena, such as overscreening and crowding. Molecular dynamics modeling reveals that the OCP arises from the alignment of the individual ion dipoles to the external electric field pulse, with the magnitude of the resulting OCP correlating with the product of the projected dipole moment of the cation and the ratio between the cation diffusion coefficient and its volume. Our findings also reveal that a stable overscreened structure is more likely to form if the interface is first forced through crowding, possibly accounting for the scattered literature data on relaxation kinetics of near-surface structures in ionic liquids.
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Affiliation(s)
- Mattia Belotti
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Xin Lyu
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Longkun Xu
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Peter Halat
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Nadim Darwish
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Debbie S Silvester
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Ching Goh
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | | | - Michelle L Coote
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Simone Ciampi
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
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19
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Cats P, van Roij R. The differential capacitance as a probe for the electric double layer structure and the electrolyte bulk composition. J Chem Phys 2021; 155:104702. [PMID: 34525830 DOI: 10.1063/5.0064315] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this work, we theoretically study the differential capacitance of an aqueous electrolyte in contact with a planar electrode, using classical density functional theory, and show how this measurable quantity can be used as a probe to better understand the structure and composition of the electric double layer at play. Specifically, we show how small trace amounts of divalent ions can influence the differential capacitance greatly and also how small ions dominate its behavior for high electrode potentials. In this study, we consider primitive model electrolytes and not only use the standard definition of the differential capacitance but also derive a new expression from mechanical equilibrium in a planar geometry. This expression reveals explicitly that the first layer of ions near the charged surface is key to its understanding. Our insights might be used as a guide in experiments to better understand the electrolyte-electrode interface as well as the (composition of the) bulk electrolyte.
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Affiliation(s)
- Peter Cats
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, Utrecht 3584 CC, The Netherlands
| | - René van Roij
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, Utrecht 3584 CC, The Netherlands
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20
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Polarization of ionic liquid and polymer and its implications for polymerized ionic liquids: An overview towards a new theory and simulation. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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21
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Zhang S, Nishi N, Katakura S, Sakka T. Evaluation of static differential capacitance at the [C 4mim +][TFSA -]/electrode interface using molecular dynamics simulation combined with electrochemical surface plasmon resonance measurements. Phys Chem Chem Phys 2021; 23:13905-13917. [PMID: 34132289 DOI: 10.1039/d1cp01435h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Molecular dynamic (MD) simulations have been performed for 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C4mim+][TFSA-]), an ionic liquid (IL), on a charged graphene electrode to achieve the quantitative analysis of the static differential capacitance using the electrochemical surface plasmon resonance (ESPR). The MD simulations have provided the surface charge density on the electrode and ionic distributions in the electric double layer, both of which are indispensable for the evaluation of static differential capacitance using ESPR but are difficult to be measured by experimental techniques. This approach has allowed the quantitative analysis and explanation of the SPR angle shift in ESPR. The major contribution to the SPR angle shift is found to be the change in ionic concentrations of the first ionic layer on the electrode, owing to higher polarizabilities of ions in the first ionic layer than those in the overlayers. Moreover, the ionic orientation on the electrode and ionic multilayer structure have also been investigated in detail. The butyl group of C4mim+ in the first ionic layer is found to provide extra room for C4mim+ in the second ionic layer but exclude TFSA-, which affects the interval and regularity of ionic multilayers.
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Affiliation(s)
- Shiwei Zhang
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.
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22
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Cruz C, Ciach A. Phase Transitions and Electrochemical Properties of Ionic Liquids and Ionic Liquid-Solvent Mixtures. Molecules 2021; 26:3668. [PMID: 34208542 PMCID: PMC8234089 DOI: 10.3390/molecules26123668] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/04/2021] [Accepted: 06/10/2021] [Indexed: 12/20/2022] Open
Abstract
Recent advances in studies of ionic liquids (IL) and ionic liquid-solvent mixtures are reviewed. Selected experimental, simulation, and theoretical results for electrochemical, thermodynamical, and structural properties of IL and IL-solvent mixtures are described. Special attention is paid to phenomena that are not predicted by the classical theories of the electrical double layer or disagree strongly with these theories. We focus on structural properties, especially on distribution of ions near electrodes, on electrical double layer capacitance, on effects of confinement, including decay length of a dissjoining pressure between confinig plates, and on demixing phase transition. In particular, effects of the demixing phase transition on electrochemical properties of ionic liquid-solvent mixtures for different degrees of confinement are presented.
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Affiliation(s)
| | - Alina Ciach
- Institute of Physical Chemistry, Polish Academy of Sciences, 44/52, 01-224 Warsaw, Poland;
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23
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A new regularity used to predict the camel-bell shape transition in the capacitance curve of electric double layer capacitors. J APPL ELECTROCHEM 2021. [DOI: 10.1007/s10800-021-01571-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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24
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Lamperski S, Bhuiyan LB. Entropy formation of an electrical double layer with divalent off-centre charge cations: Monte Carlo studies. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1918774] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Stanisław Lamperski
- Department of Physical Chemistry, Adam Mickiewicz University in Poznań, Poznań, Poland
| | - Lutful Bari Bhuiyan
- Department of Physics, Laboratory of Theoretical Physics, University of Puerto Rico, San Juan, PR, USA
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25
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Lu H, Stenberg S, Woodward CE, Forsman J. Structural transitions at electrodes, immersed in simple ionic liquid models. SOFT MATTER 2021; 17:3876-3885. [PMID: 33660732 DOI: 10.1039/d0sm02167a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We used a recently developed classical Density Functional Theory (DFT) method to study the structures, phase transitions, and electrochemical behaviours of two coarse-grained ionic fluid models, in the presence of a perfectly conducting model electrode. Common to both is that the charge of the cationic component is able to approach the electrode interface more closely than the anion charge. This means that the cations are specifically attracted to the electrode, due to surface polarization effects. Hence, for a positively charged electrode, there is competition at the surface between cations and anions, where the latter are attracted by the positive electrode charge. This generates demixing, for a range of positive voltages, where the two phases are structurally quite different. The surface charge density is also different between the two phases, even at the same potential. The DFT formulation contains an approximate treatment of ion correlations, and surface polarization, where the latter is modelled via screened image interactions. Using a mean-field DFT, where ion correlations are neglected, causes the phase transition to vanish for both models, but there is still a dramatic drop in the differential capacitance as proximal cations are replaced by anions, for increasing surface potentials. While these findings were obtained for relatively crude coarse-grained models, we argue that the findings can also be relevant in "real" systems, where we note that many ionic liquids are composed of a spherically symmetric anion, and a cation that is asymmetric both from a steric and a charge distribution point of view.
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Affiliation(s)
- Hongduo Lu
- Theoretical Chemistry, Chemical Centre, P.O. Box 124, S-221 00 Lund, Sweden.
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26
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Shin S, Greco F, Maier F, Steinrück HP. Enrichment effects of ionic liquid mixtures at polarized electrode interfaces monitored by potential screening. Phys Chem Chem Phys 2021; 23:10756-10762. [PMID: 33978646 PMCID: PMC8115399 DOI: 10.1039/d0cp04811a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The behavior of ionic liquids (ILs) at charged interfaces is pivotal for their application in supercapacitors and electrochemical cells. Recently, we demonstrated for neat ILs that potential screening at polarized electrode interfaces shows a characteristic voltage dependence, as determined in situ by X-ray photoelectron spectroscopy. Herein, we use this fingerprint-type behavior to characterize the nature of the IL/electrode interfaces for IL mixtures of [C8C1Im][Tf2N] and [C8C1Im]Cl on Au and Pt electrodes. For Au, the IL/electrode interfaces are dominated by the Cl− anions, even down to a 0.1 mol% [C8C1Im]Cl content. In contrast, [Tf2N]− anions enrich at the IL/Pt electrode interfaces down to 10 mol% [C8C1Im][Tf2N]; only at lower concentrations does a transition to Cl− enrichment occur. These mixture studies demonstrate that even small concentrations of another IL or contamination, e.g. remaining from synthesis, can strongly influence the situation at charged IL interfaces. The interface of electrodes and IL mixtures has been studied by in situ XPS. We found that the concentration of counterions at the interface can strongly deviate from the bulk composition due to interactions between electrode and IL.![]()
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Affiliation(s)
- Sunghwan Shin
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
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27
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Bryant SJ, Garcia A, Clarke RJ, Warr GG. Selective ion transport across a lipid bilayer in a protic ionic liquid. SOFT MATTER 2021; 17:2688-2694. [PMID: 33533359 DOI: 10.1039/d0sm02225j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ionic liquids (ILs) have exhibited enormous potential as electrolytes, designer solvents and reaction media, as well as being surprisingly effective platforms for amphiphile self-assembly and for preserving structure of complex biomolecules. This has led to their exploration as media for long-term biopreservation and in biosensors, for which their viability depends on their ability to sustain both structure and function within complex, multicomponent nanoscale compartments and assemblies. Here we show that a tethered lipid bilayer can be assembled directly in a purely IL environment that retains its structure upon exchange between IL and aqueous buffer, and that the membrane transporter valinomycin can be incorporated so as to retain its functionality and cation selectivity. This paves the way for the development of long-lived, non-aqueous microreactors and sensor assemblies, and demonstrates the potential for complex proteins to retain functionality in non-aqueous, ionic liquid solvents.
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Affiliation(s)
- Saffron J Bryant
- School of Chemistry, The University of Sydney, NSW 2006, Australia and School of Science, RMIT University, Melbourne, Victoria 3001, Australia.
| | - Alvaro Garcia
- School of Chemistry, The University of Sydney, NSW 2006, Australia and School of Life Sciences, University of Technology Sydney, NSW 2007, Australia
| | - Ronald J Clarke
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Gregory G Warr
- School of Chemistry, The University of Sydney, NSW 2006, Australia and University of Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
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28
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Li M, Liu S, Xie L, Yan J, Lagrost C, Wang S, Feng G, Hapiot P, Mao B. Charge Transfer Kinetics at Ag(111) Single Crystal Electrode/Ionic Liquid Interfaces: Dependence on the Cation Alkyl Side Chain Length. ChemElectroChem 2021. [DOI: 10.1002/celc.202100094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Miangang Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Shuai Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Liqiang Xie
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Jiawei Yan
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Corinne Lagrost
- Université de Rennes 1 Sciences Chimiques de Rennes (Equipe MaCSE), and CNRS, UMR No. 6226 Campus de Beaulieu. Bat 10C 35042 Rennes Cedex France
| | - Shuai Wang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan 430074 China
| | - Guang Feng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan 430074 China
| | - Philippe Hapiot
- Université de Rennes 1 Sciences Chimiques de Rennes (Equipe MaCSE), and CNRS, UMR No. 6226 Campus de Beaulieu. Bat 10C 35042 Rennes Cedex France
| | - Bingwei Mao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
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29
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Gong Z, Padua AAH. Effect of side chain modifications in imidazolium ionic liquids on the properties of the electrical double layer at a molybdenum disulfide electrode. J Chem Phys 2021; 154:084504. [PMID: 33639754 DOI: 10.1063/5.0040172] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Knowledge of how the molecular structures of ionic liquids (ILs) affect their properties at electrified interfaces is key to the rational design of ILs for electric applications. Polarizable molecular dynamics simulations were performed to investigate the structural, electrical, and dynamic properties of electric double layers (EDLs) formed by imidazolium dicyanamide ([ImX1][DCA]) at the interface with the molybdenum disulfide electrode. The effect of side chain of imidazolium on the properties of EDLs was analyzed by using 1-ethyl-3-methylimidazolium ([Im21]), 1-octyl-3-methylimidazolium ([Im81]), 1-benzyl-3-methylimidazolium ([ImB1]), and 1-(2-hydroxyethyl)-3-methylimidazolium ([ImO1]) as cations. Using [Im21] as reference, we find that the introduction of octyl or benzyl groups significantly alters the interfacial structures near the cathode because of the reorientation of cations. For [Im81], the positive charge on the cathode induces pronounced polar and non-polar domain separation. In contrast, the hydroxyl group has a minor effect on the interfacial structures. [ImB1] is shown to deliver slightly larger capacitance than other ILs even though it has larger molecular volume than [Im21]. This is attributed to the limiting factor for capacitance being the strong association between counter-ions, instead of the free space available to ions at the interface. For [Im81], the charging mechanism is mainly the exchange between anions and octyl tails, while for the other ILs, the mechanism is mainly the exchange of counter-ions. Analysis on the charging process shows that the charging speed does not correlate strongly with macroscopic bulk dynamics like viscosity. Instead, it is dominated by local displacement and reorientation of ions.
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Affiliation(s)
- Zheng Gong
- Laboratoire de Chimie, École Normale Supérieure de Lyon and CNRS, 69364 Lyon, France
| | - Agilio A H Padua
- Laboratoire de Chimie, École Normale Supérieure de Lyon and CNRS, 69364 Lyon, France
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30
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Pilkington GA, Welbourn R, Oleshkevych A, Watanabe S, Pedraz P, Radiom M, Glavatskih S, Rutland MW. Effect of water on the electroresponsive structuring and friction in dilute and concentrated ionic liquid lubricant mixtures. Phys Chem Chem Phys 2020; 22:28191-28201. [PMID: 33295339 DOI: 10.1039/d0cp05110a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of water on the electroactive structuring of a tribologically relevant ionic liquid (IL) when dispersed in a polar solvent has been investigated at a gold electrode interface using neutron reflectivity (NR). For all solutions studied, the addition of small amounts of water led to clear changes in electroactive structuring of the IL at the electrode interface, which was largely determined by the bulk IL concentration. At a dilute IL concentration, the presence of water gave rise to a swollen interfacial structuring, which exhibited a greater degree of electroresponsivity with applied potential compared to an equivalent dry solution. Conversely, for a concentrated IL solution, the presence of water led to an overall thinning of the interfacial region and a crowding-like structuring, within which the composition of the inner layer IL layers varied systematically with applied potential. Complementary nanotribotronic atomic force microscopy (AFM) measurements performed for the same IL concentration, in dry and ambient conditions, show that the presence of water reduces the lubricity of the IL boundary layers. However, consistent with the observed changes in the IL layers observed by NR, reversible and systematic control of the friction coefficient with applied potential was still achievable. Combined, these measurements provide valuable insight into the implications of water on the interfacial properties of ILs at electrified interfaces, which inevitably will determine their applicability in tribotronic and electrochemical contexts.
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Affiliation(s)
- Georgia A Pilkington
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
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31
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Chávez-Navarro MA, González-Tovar E, Chávez-Páez M. Enhanced charge reversal and charge amplification in a shape- and size-asymmetric electric double layer: the effect of big ions. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1791368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- M. A. Chávez-Navarro
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - E. González-Tovar
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - M. Chávez-Páez
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
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32
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Zhang M, Duan S, Luo S, Zhong Y, Yan J, Liu G, Mao B, Tian Z. Structural Exploration of Multilayered Ionic Liquid/Ag Electrode Interfaces by Atomic Force Microscopy and Surface‐Enhanced Raman Spectroscopy. ChemElectroChem 2020. [DOI: 10.1002/celc.202001294] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Meng Zhang
- State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Sai Duan
- Collaborative Innovation Center of Chemistry for Energy Materials Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials MOE Key Laboratory of Computational Physical Sciences Department of Chemistry Fudan University Shanghai 200433 P. R. China
| | - Siheng Luo
- State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
- State Key Laboratory of Marine Environmental Science Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies Center for Marine Environmental Chemistry & Toxicology College of the Environment and Ecology Xiamen University Xiamen 361102 China
| | - Yunxin Zhong
- State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Jiawei Yan
- State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Guokun Liu
- State Key Laboratory of Marine Environmental Science Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies Center for Marine Environmental Chemistry & Toxicology College of the Environment and Ecology Xiamen University Xiamen 361102 China
| | - Bingwei Mao
- State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Zhongqun Tian
- State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
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33
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de Souza JP, Goodwin ZAH, McEldrew M, Kornyshev AA, Bazant MZ. Interfacial Layering in the Electric Double Layer of Ionic Liquids. PHYSICAL REVIEW LETTERS 2020; 125:116001. [PMID: 32975984 DOI: 10.1103/physrevlett.125.116001] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Ions in ionic liquids and concentrated electrolytes reside in a crowded, strongly interacting environment, leading to the formation of discrete layers of charges at interfaces and spin-glass structure in the bulk. Here, we propose a simple theory that captures the coupling between steric and electrostatic forces in ionic liquids. The theory predicts the formation of discrete layers of charge at charged interfaces. Further from the interface, or at low polarization of the electrode, the model outputs slowly decaying oscillations in the charge density with a wavelength of a single ion diameter, as shown by analysis of the gradient expansion. The gradient expansion suggests a new structure for partial differential equations describing the electrostatic potential at charged interfaces. We find quantitative agreement between the theory and molecular simulations in the differential capacitance and concentration profiles.
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Affiliation(s)
- J Pedro de Souza
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Zachary A H Goodwin
- Department of Physics, CDT Theory and Simulation of Materials, Imperial College of London, South Kensington Campus, London SW7 2AZ, United Kingdom
- Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Michael McEldrew
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Alexei A Kornyshev
- Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
- Department of Chemistry, Imperial College of London, Molecular Science Research Hub, White City Campus, London W12 0BZ, United Kingdom
| | - Martin Z Bazant
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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To evaluate an ionic liquid for anticorrosive impact on iron–carbon steel: synthesis, computational and experimental mechanism. CHEMICAL PAPERS 2020. [DOI: 10.1007/s11696-020-01341-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Quadre AB, de Carvalho SJ, Bossa GV. How charge regulation and ion-surface affinity affect the differential capacitance of an electrical double layer. Phys Chem Chem Phys 2020; 22:18229-18238. [PMID: 32776041 DOI: 10.1039/d0cp02360d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The differential capacitance of an electrical double layer is a topic of great importance to develop more efficient and environment-friendly energy storage devices: electric double layer supercapacitors. In addition to the bare electrostatic interactions, recent experimental and computational studies suggest that electrodes covered by ionizable groups do interact selectively with specific ion types, an effect that can increase the maximal conductivity and voltage of a supercapacitor. Inspired by this, in the present work we investigate how ion-specific non-electrostatic interactions modify the differential capacitance of a flat electrode whose surface is covered by ionizable groups subject to a charge regulation process. The incorporation of hydration interactions by means of ion-specific Yukawa potential into the Poisson-Boltzmann theory allows our model to describe different scenarios of ion-surface affinity and, hence, the selective depletion or accumulation of specific ion types close to a charged surface. We obtained larger capacitance values when considering electrodes that favor the accumulation of cations and the depletion of anions.
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Affiliation(s)
- Amanda B Quadre
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil.
| | - Sidney J de Carvalho
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil.
| | - Guilherme Volpe Bossa
- Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil.
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Zhang S, Nishi N, Sakka T. Electrochemical surface plasmon resonance measurements of camel-shaped static capacitance and slow dynamics of electric double layer structure at the ionic liquid/electrode interface. J Chem Phys 2020; 153:044707. [PMID: 32752680 DOI: 10.1063/5.0011671] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Electrochemical surface plasmon resonance (ESPR) is applied to evaluate the relative static differential capacitance at the interface between 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ionic liquid (IL) and a gold electrode, based on the relationship between the SPR angle and surface charge density on the electrode. Potential-step and potential-scan ESPR measurements are used to probe the dynamics of the electric double layer (EDL) structure that exhibit anomalously slow and asymmetrical characteristics depending on the direction of potential perturbation. EDL dynamics respond at least 30 times more slowly to changes of potential in the positive direction than in the negative direction. ESPR experiments with the positive-going potential scan are significantly affected by the slow dynamics even at a slow scan. The surface charge density that reflects the relative static capacitance is obtained from the negative-going potential scans. The evaluated quasi-static differential capacitance exhibits a camel-shaped potential dependence, thereby agreeing with the prediction of the mean-field lattice gas model of the EDL in ILs. ESPR is shown to be an effective experimental method for determining relative values of the static differential capacitance.
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Affiliation(s)
- Shiwei Zhang
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Naoya Nishi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - Tetsuo Sakka
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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Bhardwaj K, Parvis F, Wang Y, Blanchard GJ, Swain GM. Effect of Surface Oxygen on the Wettability and Electrochemical Properties of Boron-Doped Nanocrystalline Diamond Electrodes in Room-Temperature Ionic Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5717-5729. [PMID: 32348147 DOI: 10.1021/acs.langmuir.0c00294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This paper reports on how the surface chemistry of boron-doped nanocrystalline diamond (BDD) thin-film electrodes (H vs O) affects the wettability and electrochemical properties in two room-temperature ionic liquids (RTILs): [BMIM][PF6] and [HMIM][PF6]. Comparative measurements were made in 0.5 mol L-1 H2SO4. The BDD electrodes were modified by microwave or radio-frequency (RF) plasma treatment in H2 (H-BDD), Ar (Ar-BDD), or O2 (O-BDD). These modifications produced low-, medium-, and high-oxygen surface coverages. Atomic O/C ratios, as determined by X-ray photoelectron spectroscopy (XPS), were 0.01 for H-BDD, 0.08 for Ar-BDD, and 0.17 for O-BDD. The static contact angle of ultrapure water on the modified electrodes decreased from 110° (H-BDD) to 41° (O-BDD) with increasing surface oxygen coverage, as expected as the surface becomes more hydrophilic. Interestingly, the opposite trend was seen for both RTILs as the contact angle increased from 20° (H-BDD) to 50° (O-BDD) with increasing surface oxygen coverage. The cyclic voltammetric background current and potential-dependent capacitance in both RTILs were largest for BDD electrodes with the lowest O/C ratio (H-BDD) and smallest contact angle. Slightly larger voltammetric background currents and capacitance were observed in [HMIM][PF6] than in [BMIM][PF6]. Capacitance values ranged from 8 to 16 μF cm-2 over the potential range for H-BDD and from 4 to 6 μF cm-2 for O-BDD. The opposite trend was observed in H2SO4 as the voltammetric background current and capacitance were largest for BDD electrodes with the highest O/C ratio (O-BDD) and smallest contact angle. In summary, reducing the surface oxygen on BDD electrodes increases the wettability to two RTILs and this increases the voltammetric background current and capacitance.
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Affiliation(s)
- Kirti Bhardwaj
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
- Department of Chemical Engineering and Material Science, Michigan State University, 428 South Shaw Lane, East Lansing, Michigan 48824-1226, United States
| | - FatemehSadat Parvis
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Yufeng Wang
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Gary J Blanchard
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Greg M Swain
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
- Department of Chemical Engineering and Material Science, Michigan State University, 428 South Shaw Lane, East Lansing, Michigan 48824-1226, United States
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Schwarz K, Sundararaman R. The electrochemical interface in first-principles calculations. SURFACE SCIENCE REPORTS 2020; 75:10.1016/j.surfrep.2020.100492. [PMID: 34194128 PMCID: PMC8240516 DOI: 10.1016/j.surfrep.2020.100492] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
First-principles predictions play an important role in understanding chemistry at the electrochemical interface. Electronic structure calculations are straightforward for vacuum interfaces, but do not easily account for the interfacial fields and solvation that fundamentally change the nature of electrochemical reactions. Prevalent techniques for first-principles prediction of electrochemical processes range from expensive explicit solvation using ab initio molecular dynamics, through a hierarchy of continuum solvation techniques, to neglecting solvation and interfacial field effects entirely. Currently, no single approach reliably captures all relevant effects of the electrochemical double layer in first-principles calculations. This review systematically lays out the relation between all major approaches to first-principles electrochemistry, including the key approximations and their consequences for accuracy and computational cost. Focusing on ab initio methods for thermodynamic properties of aqueous interfaces, we first outline general considerations for modeling electrochemical interfaces, including solvent and electrolyte dynamics and electrification. We then present the specifics of various explicit and implicit models of the solvent and electrolyte. Finally, we discuss the compromise between computational efficiency and accuracy, and identify key outstanding challenges and future opportunities in the wide range of techniques for first-principles electrochemistry.
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Affiliation(s)
- Kathleen Schwarz
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, USA
| | - Ravishankar Sundararaman
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 8th St., Troy, New York 12180, USA
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Hjalmarsson N, Bergendal E, Wang YL, Munavirov B, Wallinder D, Glavatskih S, Aastrup T, Atkin R, Furó I, Rutland MW. Electro-Responsive Surface Composition and Kinetics of an Ionic Liquid in a Polar Oil. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15692-15700. [PMID: 31581771 DOI: 10.1021/acs.langmuir.9b02119] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The quartz crystal microbalance (QCM) has been used to study how the interfacial layer of an ionic liquid dissolved in a polar oil at low weight percentages responds to changes in applied potential. The changes in surface composition at the QCM gold surface depend on both the magnitude and sign of the applied potential. The time-resolved response indicates that the relaxation kinetics are limited by the diffusion of ions in the interfacial region and not in the bulk, since there is no concentration dependence. The measured mass changes cannot be explained only in terms of simple ion exchange; the relative molecular volumes of the ions and the density changes in response to ion exclusion must be considered. The relaxation behavior of the potential between the electrodes upon disconnecting the applied potential is more complex than that observed for pure ionic liquids, but a measure of the surface charge can be extracted from the exponential decay when the rapid initial potential drop is accounted for. The adsorbed film at the gold surface consists predominantly of ionic liquid despite the low concentration, which is unsurprising given the surtactant-like structures of (some of) the ionic liquid ions. Changes in response to potential correspond to changes in the relative numbers of cations and anions, rather than a change in the oil composition. No evidence for an electric field induced change in viscosity is observed. This work shows conclusively that electric potentials can be used to control the surface composition, even in an oil-based system, and paves the way for other ion solvent studies.
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Affiliation(s)
| | | | | | | | | | - Sergei Glavatskih
- Department of Electrical Energy, Metals, Mechanical Constructions and Systems , Ghent University , B-9000 , Ghent , Belgium
| | | | - Rob Atkin
- School of Molecular Sciences , University of Western Australia , 6009 Perth , Australia
| | | | - Mark W Rutland
- Surfaces, Processes and Formulation , RISE Research Institutes of Sweden , SE-50115 Stockholm , Sweden
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40
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Mao X, Brown P, Červinka C, Hazell G, Li H, Ren Y, Chen D, Atkin R, Eastoe J, Grillo I, Padua AAH, Costa Gomes MF, Hatton TA. Self-assembled nanostructures in ionic liquids facilitate charge storage at electrified interfaces. NATURE MATERIALS 2019; 18:1350-1357. [PMID: 31406367 DOI: 10.1038/s41563-019-0449-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 07/01/2019] [Indexed: 05/23/2023]
Abstract
Driven by the potential applications of ionic liquids (ILs) in many emerging electrochemical technologies, recent research efforts have been directed at understanding the complex ion ordering in these systems, to uncover novel energy storage mechanisms at IL-electrode interfaces. Here, we discover that surface-active ILs (SAILs), which contain amphiphilic structures inducing self-assembly, exhibit enhanced charge storage performance at electrified surfaces. Unlike conventional non-amphiphilic ILs, for which ion distribution is dominated by Coulombic interactions, SAILs exhibit significant and competing van der Waals interactions owing to the non-polar surfactant tails, leading to unusual interfacial ion distributions. We reveal that, at an intermediate degree of electrode polarization, SAILs display optimum performance, because the low-charge-density alkyl tails are effectively excluded from the electrode surfaces, whereas the formation of non-polar domains along the surface suppresses undesired overscreening effects. This work represents a crucial step towards understanding the unique interfacial behaviour and electrochemical properties of amphiphilic liquid systems showing long-range ordering, and offers insights into the design principles for high-energy-density electrolytes based on spontaneous self-assembly behaviour.
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Affiliation(s)
- Xianwen Mao
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
| | - Paul Brown
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ctirad Červinka
- Laboratoire de Chimie, Ecole Normale Supérieure de Lyon and CNRS, Lyon, France
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Czech Republic
| | - Gavin Hazell
- Department of Natural Sciences, University of Chester, Chester, UK
| | - Hua Li
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Yinying Ren
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Di Chen
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Julian Eastoe
- School of Chemistry, University of Bristol, Bristol, UK
| | | | - Agilio A H Padua
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Laboratoire de Chimie, Ecole Normale Supérieure de Lyon and CNRS, Lyon, France
| | - Margarida F Costa Gomes
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Laboratoire de Chimie, Ecole Normale Supérieure de Lyon and CNRS, Lyon, France.
| | - T Alan Hatton
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Gallegos A, Lian C, Dyatkin B, Wu J. Side-chain effects on the capacitive behaviour of ionic liquids in microporous electrodes. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1650210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Alejandro Gallegos
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USA
| | - Cheng Lian
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, PR People’s Republic of China
| | - Boris Dyatkin
- A.J. Drexel Nanomaterials Institute and the Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA
| | - Jianzhong Wu
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USA
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Curvature dependence of the camel-bell curve transition on the capacitance curve of spherical electric double-layer in porous electrodes: Density Functional Theory. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.05.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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44
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Lamperski S, Henderson D, Bhuiyan LB. Off-centre charge model of the planar electric double layer for asymmetric 2:1/1:2 valencies. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1642527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Stanisław Lamperski
- Department of Physical Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań, Poland
| | - Douglas Henderson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Lutful Bari Bhuiyan
- Laboratory of Theoretical Physics, Department of Physics, University of Puerto Rico, San Juan, PR, USA
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Hou X, Wang Z, Zheng Z, Guo J, Sun Z, Yan F. Poly(ionic liquid) Electrolytes for a Switchable Silver Mirror. ACS APPLIED MATERIALS & INTERFACES 2019; 11:20417-20424. [PMID: 31070033 DOI: 10.1021/acsami.9b05001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Imidazolium-type small-molecule ionic liquids (ILs) and their corresponding poly(ionic liquid) (PIL) homopolymers were synthesized and applied to reversible electrochemical mirrors (REMs). The effects of alkyl chain length of the carbon chains at the N3 position and cation charge density (mono- and bis-imidazolium) on the electrochromic properties of Ag-based REMs were investigated by analyzing their electrodeposition and spectral properties. Longer alkyl chains and higher charge densities decreased the size and resulted in a more uniform distribution of Ag nanoparticles. Compared with IL-based liquid electrolytes, the PIL-based gel electrolytes formed smaller and denser electrodeposited metallic Ag nanoparticles because of their higher viscosity. These findings were used to guide fabrication of a 50 cm2 mirror dynamic window and flexible display. Because of several unique properties of PILs, the PIL-based REM exhibits fast switching speeds, superb cycling durability, small particle sizes, and uniform electrodeposited Ag nanoparticle films. These results make dynamic windows based on PIL electrolytes promising and competitive alternatives to traditional electrochromic windows.
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Affiliation(s)
- Xiao Hou
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
| | - Zhenyong Wang
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
| | - Zhiqiang Zheng
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
| | - Jiangna Guo
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
| | - Zhe Sun
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
| | - Feng Yan
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , China
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Abstract
Ionic liquids have become of significant relevance in chemistry, as they can serve as environmentally-friendly solvents, electrolytes, and lubricants with bespoke properties. In particular for electrochemical applications, an understanding of the interface structure between the ionic liquid and an electrified interface is needed to model and optimize the reactions taking place on the solid surface. As with ionic liquids, the interplay between electrostatic forces and steric effects leads to an intrinsic heterogeneity, as the structure of the ionic liquid above an electrified interface cannot be described by the classical electrical double layer model. Instead, a layered solvation layer is present with a structure that depends on the material combination of the ionic liquid and substrate. In order to experimentally monitor this structure, atomic force spectroscopy (AFS) has become the method of choice. By measuring the force acting on a sharp microfabricated tip while approaching the surface in an ionic liquid, it has become possible to map the solvation layers with sub-nanometer resolution. In this review, we provide an overview of the AFS studies on ionic liquids published in recent years that illustrate how the interface is formed and how it can be modified by applying electrical potential or by adding impurities and solvents.
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Kłos J, Lamperski S. Electrical double layer in molten salts with account of soft repulsions. J Chem Phys 2019; 150:184703. [PMID: 31091935 DOI: 10.1063/1.5093198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Results of Monte Carlo simulations of the electrode-molten salt interface are reported. The system was modeled by soft ions in contact with a soft wall using the Lennard-Jones potential restricted to the repulsion part. The soft wall was formed of C (graphite), Hg, and Pb atoms. Calculations were carried out for the parameter values which would permit making comparison with the real system. The paper presents information on physicochemical properties of the interfacial region, such as the ion singlet distribution functions, the mean electrostatic potential as a function of the distance from the electrode surface, and differential capacitance results as a function of the electrode charges. The differential capacitance curves have a flat and distorted bell shape which vary depending on the kind of the electrode material. The differential capacitance results are discussed and compared with the data obtained from ionic liquid simulations, density functional theory, and mean field calculations.
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Affiliation(s)
- Jacek Kłos
- Department of Physical Chemistry, Faculty of Chemistry, A. Mickiewicz University of Poznań, Ul. Umultowska 89b, 61-614 Poznań, Poland
| | - Stanisław Lamperski
- Department of Physical Chemistry, Faculty of Chemistry, A. Mickiewicz University of Poznań, Ul. Umultowska 89b, 61-614 Poznań, Poland
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Noh C, Jung Y. Understanding the charging dynamics of an ionic liquid electric double layer capacitor via molecular dynamics simulations. Phys Chem Chem Phys 2019; 21:6790-6800. [PMID: 30735216 DOI: 10.1039/c8cp07200k] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We investigate the charging phenomena of an electric double layer capacitor (EDLC) by conducting both equilibrium and non-equilibrium molecular dynamics (MD) simulations. A graphene electrode and 1-ethyl-3-methylimidazolium thiocyanate ([EMIM]+[SCN]-) ionic liquid were used as a system for the EDLC. We clarify the ionic layer structure and show that an abrupt change of the ionic layers leads to a high differential capacitance of the EDLC. The charging simulations reveal that the charging dynamics of the EDLC is highly dependent on the rearrangement of the ionic layer structure. Particularly, the electrode charge during the charging process is consistent with the perpendicular displacement of ionic liquid molecules. From this property, we analyze the contribution of each molecular ion to the electrode charge stored during charging. Charging of the EDLC is largely dependent on the desorption of the co-ions from the electrode rather than the adsorption of the counter-ions. In addition, the contribution of bulk ions to the charge stored in the EDLC is as important as that of ions adjacent to the electrode surface contrary to the conventional viewpoint. From these results, we identify the charging mechanism of the EDLC and discuss the relevance to experimental results. Our findings in the present study are expected to play an important role in designing an efficient EDLC with a novel perspective on the charging of the EDLC.
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Affiliation(s)
- Chanwoo Noh
- Department of Chemistry, Seoul National University, Seoul 08826, Korea.
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Stockmann TJ, Lemineur JF, Liu H, Cometto C, Robert M, Combellas C, Kanoufi F. Single LiBH4 nanocrystal stochastic impacts at a micro water|ionic liquid interface. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2018.12.105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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50
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Kłos J, Lamperski S. Analysis of electrical double layer structure in molten salts. J Chem Phys 2019; 150:064704. [PMID: 30769969 DOI: 10.1063/1.5082561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This paper reports the results of analysis of the electrical double layer (EDL) phenomenon in molten salts to provide information on the influence of short range interaction type on the shape of charge distribution and the effect of the charge distribution shape on capacitance values. A new method of analysis is proposed, which allows a quantitative discussion. It is assumed that EDL can be modelled as a number of capacitor plates connected in series. This paper reports the application of the proposed method in quantitative analysis of the molten salt capacitance data obtained for different short range potentials. The data to be analysed were obtained from the Monte Carlo simulations of the symmetrical molten salt electrolyte for the following short range interaction potentials: hard spheres, Lennard-Jones repulsions, and full Lennard-Jones. The new analysis method gives a more detailed understanding of EDL in molten salts and can become an inspiration for new researches in this field.
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Affiliation(s)
- Jacek Kłos
- Department of Physical Chemistry, Faculty of Chemistry, A. Mickiewicz University of Poznań, ul. Umultowska 89b, 61-614 Poznań, Poland
| | - Stanisław Lamperski
- Department of Physical Chemistry, Faculty of Chemistry, A. Mickiewicz University of Poznań, ul. Umultowska 89b, 61-614 Poznań, Poland
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