1
|
Goodwin ZAH, Wenny MB, Yang JH, Cepellotti A, Ding J, Bystrom K, Duschatko BR, Johansson A, Sun L, Batzner S, Musaelian A, Mason JA, Kozinsky B, Molinari N. Transferability and Accuracy of Ionic Liquid Simulations with Equivariant Machine Learning Interatomic Potentials. J Phys Chem Lett 2024; 15:7539-7547. [PMID: 39023916 DOI: 10.1021/acs.jpclett.4c01942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Ionic liquids (ILs) are an exciting class of electrolytes finding applications in many areas from energy storage to solvents, where they have been touted as "designer solvents" as they can be mixed to precisely tailor the physiochemical properties. As using machine learning interatomic potentials (MLIPs) to simulate ILs is still relatively unexplored, several questions need to be answered to see if MLIPs can be transformative for ILs. Since ILs are often not pure, but are either mixed together or contain additives, we first demonstrate that a MLIP can be trained to be compositionally transferable; i.e., the MLIP can be applied to mixtures of ions not directly trained on, while only being trained on a few mixtures of the same ions. We also investigated the accuracy of MLIPs for a novel IL, which we experimentally synthesize and characterize. Our MLIP trained on ∼200 DFT frames is in reasonable agreement with our experiments and DFT.
Collapse
Affiliation(s)
- Zachary A H Goodwin
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Malia B Wenny
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Julia H Yang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Harvard University Center for the Environment, 26 Oxford St., Cambridge, Massachusetts 02138, United States
| | - Andrea Cepellotti
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jingxuan Ding
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Kyle Bystrom
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Blake R Duschatko
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Anders Johansson
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Lixin Sun
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Simon Batzner
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Albert Musaelian
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jarad A Mason
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Boris Kozinsky
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Research and Technology Center, Robert Bosch LLC, Cambridge, Massachusetts 02142, United States
| | - Nicola Molinari
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Research and Technology Center, Robert Bosch LLC, Cambridge, Massachusetts 02142, United States
| |
Collapse
|
2
|
Bi S, Salanne M. Cluster analysis as a tool for quantifying structure-transport properties in simulations of superconcentrated electrolyte. Chem Sci 2024; 15:10908-10917. [PMID: 39027304 PMCID: PMC11253178 DOI: 10.1039/d4sc01491j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 06/09/2024] [Indexed: 07/20/2024] Open
Abstract
Using molecular dynamics simulations and graph-theory-based cluster analysis, we investigate the structure-transport properties of typical water-in-salt electrolytes. We demonstrate that ions exhibit distinct dynamics across different ionic clusters-namely, solvent-separated ion pairs (SSIPs), contact ion pairs (CIPs), and aggregates (AGGs). We assess the average proportions of various ionic species and their lifetimes. Our method reveals a dynamic decoupling of ion kinetics, with each species independently contributing to the overall molecular motion. This is evidenced by the fact that the total velocity autocorrelation function (VACF) and power spectrum can be expressed as a weighted sum of independent functions for each species. The experimental data on the ionic conductivity of the studied LiTFSI electrolytes align well with our theoretical predictions at various concentrations, based on the proportions and diffusion coefficients of free ions derived from our analysis. The insights gained into the solvation structures and dynamics of different ionic species enable us to elucidate the physical mechanisms driving ion transport in such superconcentrated electrolytes, providing a comprehensive framework for the future design and optimization of electrolytes.
Collapse
Affiliation(s)
- Sheng Bi
- Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux F-75005 Paris France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 80039 Amiens Cedex France
| | - Mathieu Salanne
- Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux F-75005 Paris France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 80039 Amiens Cedex France
- Institut Universitaire de France (IUF) 75231 Paris France
| |
Collapse
|
3
|
Zhang S, Wu S, Hwang J, Matsumoto K, Hagiwara R. Unprotected Organic Cations─The Dilemma of Highly Li-Concentrated Ionic Liquid Electrolytes. J Am Chem Soc 2024; 146:8352-8361. [PMID: 38494762 DOI: 10.1021/jacs.3c14110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Highly Li-concentrated electrolytes have been widely studied to harness their uniquely varying bulk and interface properties that arise from their distinctive physicochemical properties and coordination structures. Similar strategies have been applied in the realm of ionic liquid electrolytes to exploit their improved functionalities. Despite these prospects, the impact of organic cation behavior on interfacial processes remains largely underexplored compared to the widely studied anion behavior. The present study demonstrates that the weakened interactions between cations and anions engender "unprotected" organic cations in highly Li-concentrated ionic liquid electrolytes, leading to the decomposition of electrolytes during the initial charge. This decomposition behavior is manifested by the substantial irreversible capacities and inferior initial Coulombic efficiencies observed during the initial charging of graphite negative electrodes, resulting in considerable electrolyte consumption and diminished energy densities in full-cell configurations. The innate cation behavior is ascertained by examining the coordination environment of ionic liquid electrolytes with varied Li concentrations, where intricate ionic interactions between organic cations and anions are unveiled. In addition, anionic species with high Lewis basicity were introduced to reinforce the ionic interactions involving organic cations and improve the initial Coulombic efficiency. This study verifies the role of unprotected organic cations while highlighting the significance of the coordination environment in the performance of ionic liquid electrolytes.
Collapse
Affiliation(s)
- Shaoning Zhang
- Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shengan Wu
- Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Jinkwang Hwang
- Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhiko Matsumoto
- Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Rika Hagiwara
- Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| |
Collapse
|
4
|
Firth AJ, Nakasu PYS, Hallett JP, Matthews RP. Exploiting Cation Structure and Water Content in Modulating the Acidity of Ammonium Hydrogen Sulfate Protic Ionic Liquids. J Phys Chem Lett 2024; 15:2311-2318. [PMID: 38386631 PMCID: PMC10926163 DOI: 10.1021/acs.jpclett.3c03583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/07/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
In this paper, we investigated the effect of cation structure and water content on proton dissociation in alkylammonium [HSO4]- protic ionic liquids (ILs) doped with 20 wt % water and correlated this with experimental Hammett acidities. For pure systems, increased cation substitution resulted in a reduction in the number of direct anion-anion neighbors leading to larger numbers of small aggregates, which is further enhanced with addition of water. We also observed spontaneous proton dissociation from [HSO4]- to water only for primary amine-based protic ILs, preceded by the formation of an anion trimer motif. Investigation using DFT calculations revealed spontaneous proton dissociation from [HSO4]- to water can occur for each of the protic ILs investigated; however, this is dependent on the size of the anion aggregates. These findings are important in the fields of catalysis and lignocellulosic biomass, where solvent acidity is a crucial parameter in biomass fractionation and lignin chemistry.
Collapse
Affiliation(s)
- Anton
E. J. Firth
- Department
of Chemical Engineering, Imperial College
London, London SW7 2AZ, U.K.
| | - Pedro Y. S. Nakasu
- Department
of Chemical Engineering, Imperial College
London, London SW7 2AZ, U.K.
| | - Jason P. Hallett
- Department
of Chemical Engineering, Imperial College
London, London SW7 2AZ, U.K.
| | - Richard P. Matthews
- Department
of Chemical Engineering, Imperial College
London, London SW7 2AZ, U.K.
- Department
of Bioscience, School of Health, Sports and Bioscience, University of East London, Stratford, London E15 4LZ, U.K.
| |
Collapse
|
5
|
Yamaguchi T, Dukhin A, Ryu YJ, Zhang D, Borodin O, González MA, Yamamuro O, Price DL, Saboungi ML. Non-Newtonian Dynamics in Water-in-Salt Electrolytes. J Phys Chem Lett 2024; 15:76-80. [PMID: 38133800 DOI: 10.1021/acs.jpclett.3c03145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Water-in-salt electrolytes have attracted considerable interest in the past decade for advanced lithium-ion batteries, possessing important advantages over the non-aqueous electrolytes currently in use. A battery with a LiTFSI-water electrolyte was demonstrated in which an operating window of 3 V is made possible by a solid-electrolyte interface. Viscosity is an important property for such electrolytes, because high viscosity is normally associated with low ionic conductivity. Here, we investigate shear and longitudinal viscosities using shear stress and compressional longitudinal stress measurements as functions of frequency and concentration. We find that both viscosities are frequency-dependent and exhibit almost identical frequency and concentration dependences in the high-concentration region. A comparison to quasielastic neutron scattering experiments suggests that both are governed by structural relaxation of the TFSI- network. Thus, LiFTSI-water electrolytes appear to be an unusual case of a non-Newtonian fluid, where shear and longitudinal viscosities are determined by the same relaxation mechanism.
Collapse
Affiliation(s)
- Tsuyoshi Yamaguchi
- Graduate School of Engineering, Nagoya University, Furocho, Chikusa, Nagoya, Aichi 464-8603, Japan
| | - Andrei Dukhin
- Dispersion Technology, Incorporated, 364 Adams Street, Bedford Hills, New York 10507, United States
| | - Young-Jay Ryu
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Dongzhou Zhang
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Oleg Borodin
- Energy Storage Branch, Sensor and Electron Devices Directorate, United States Army Research Laboratory, Adelphi, Maryland 20783, United States
| | - Miguel A González
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Osamu Yamamuro
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - David L Price
- CNRS and Université d'Orléans, CEMHTI, 1D Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France
| | | |
Collapse
|
6
|
Ahmed MD, Zhu Z, Khamzin A, Paddison SJ, Sokolov AP, Popov I. Effect of Ion Mass on Dynamic Correlations in Ionic Liquids. J Phys Chem B 2023; 127:10411-10421. [PMID: 38012530 DOI: 10.1021/acs.jpcb.3c05568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Ionic liquids (ILs) are a class of liquid salts with distinct properties such as high ionic conductivity, low volatility, and a broad electrochemical window, making them appealing for use in energy storage applications. The ion-ion correlations are some of the key factors that play a critical role in the ionic conductivity of ILs. In this work, we present the study of the impact of ion mass on ion-ion correlations in ILs, applying a combination of broadband dielectric spectroscopy measurements and molecular dynamics simulations. We examined three ILs with the same cation but different anions to consider three different cases of cation-anion masses: M+ > M-, M+ ≈ M-, and M+ < M-. We applied the momentum conservation approach to estimate the contribution of distinct ion-ion correlations from experimental data and obtained good agreement with direct calculations of distinct ion-ion correlations from molecular dynamics simulations. Our findings reveal that relative ion mass has a strong effect on the distinct ion-ion correlations, leading to swapping of the relative amplitude of distinct cation-cation and anion-anion correlations.
Collapse
Affiliation(s)
- Md Dipu Ahmed
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Zhenghao Zhu
- Department of Chemical Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Airat Khamzin
- Institute of Physics, Kazan Federal University, Kremlevskaya Str. 18, Kazan 420008, Russia
| | - Stephen J Paddison
- Department of Chemical Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Alexei P Sokolov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ivan Popov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
- University of Tennessee─Oak Ridge Innovation Institute, University of Tennessee, Knoxville, Tennessee 37996, United States
| |
Collapse
|
7
|
Ren X, Yan T. Molecular Dynamics Simulation on the Charge Transport Properties in a Salt-in-Ionic Liquid Electrolyte. J Phys Chem B 2023; 127:10434-10446. [PMID: 38008915 DOI: 10.1021/acs.jpcb.3c05973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
A clear picture of charge transport properties in salt-in-ionic liquid electrolyte (SILE) is indispensable for the applications in lithium-ion batteries. In this study, we applied molecular dynamics (MD) simulations on a typical SILE system, composed of lithium bis(fluorosulfonyl)imide (LiFSI) with a molar fraction of 0.3 doped in 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIMFSI). Based on the MD simulations, we calculated conductivity spectra from 108 Hz to 1014 Hz, charge current correlation functions, and charge mean square displacements, based on the center-of-mass (COM) velocities of the ions. The conductivity spectra show a bimodal feature between 1012 Hz and 1013 Hz, attributed to the interionic vibrations of the EMIM+-FSI- and Li+-FSI- contact ion pairs, respectively. Structural relaxation is observed between 109 Hz and 1012 Hz, and a flat plateau below 109 Hz, attributed to the direct current (DC) conductivity. For this SILE composed of three constituent ions, i.e., Li+, EMIM+, and FSI-, the above transport properties are further partitioned to the contributions of the individual constituent ions, including self, distinct contribution of the same constituent ions, and also the cross correlation between them. Detailed analyses on the individual contributions reveal strongly correlated motions in this complex ionic system.
Collapse
Affiliation(s)
- Xiaozhe Ren
- Institute of New Energy Material Chemistry, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| | - Tianying Yan
- Institute of New Energy Material Chemistry, School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| |
Collapse
|
8
|
Lee Y, Cho J, Kim J, Lee WB, Jho Y. Anomalous diffusion of lithium-anion clusters in ionic liquids. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:105. [PMID: 37917274 DOI: 10.1140/epje/s10189-023-00365-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/12/2023] [Indexed: 11/04/2023]
Abstract
Lithium-ion transport is significantly retarded in ionic liquids (ILs). In this work, we performed extensive molecular dynamics simulations to mimic the kinetics of lithium ions in ILs using [N-methyl-N-propylpyrrolidium (pyr[Formula: see text])][bis(trifluoromethanesulfonyl)imide (Ntf[Formula: see text])] with added LiNtf[Formula: see text] salt. And we analyzed their transport, developing a two-state model and comparing it to the machine learning-identified states. The transport of lithium ions involves local shell exchanges of the Ntf[Formula: see text] in the medium. We calculated train size distributions over various time scales. The train size distribution decays as a power law, representing non-Poissonian bursty shell exchanges. We analyzed the non-Poissonian processes of lithium ions transport as a two-state (soft and hard) model. We analytically calculated the transition probability of the two-state model, which fits well to the lifetime autocorrelation functions of LiNtf[Formula: see text] shells. To identify two states, we introduced the graph neutral network incorporating local molecular structure. The results reveal that the shell-soft state mainly contributes to the transport of the lithium ions, and their contribution is more important in low temperatures. Hence, it is the key for enhanced lithium ion transport to increase the fraction of the shell-soft state.
Collapse
Affiliation(s)
- YeongKyu Lee
- Department of Physics, Gyeongsang National University, Jinjudae-ro 501, Jinju, Gyeongsangnam-do, 52828, Republic of Korea
| | - JunBeom Cho
- School of Chemical and Biological Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Junseong Kim
- Department of Physics, Gyeongsang National University, Jinjudae-ro 501, Jinju, Gyeongsangnam-do, 52828, Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
| | - YongSeok Jho
- Department of Physics, Gyeongsang National University, Jinjudae-ro 501, Jinju, Gyeongsangnam-do, 52828, Republic of Korea.
| |
Collapse
|
9
|
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: 4] [Impact Index Per Article: 4.0] [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.
Collapse
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
| |
Collapse
|
10
|
Dziubinska-Kühn K, Maddah M, Pupier M, Matysik J, Viger-Gravel J, Kowalska M, Karg B. Influence of alkali metals on water dynamics inside imidazolium-based ionic liquid nano-domains. Front Chem 2022; 10:1028912. [DOI: 10.3389/fchem.2022.1028912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022] Open
Abstract
The global need to expand the design of energy-storage devices led to the investigation of alkali metal - Ionic Liquid (IL) mixtures as a possible class of electrolytes. In this study, 1D and 2D Nuclear Magnetic Resonance (NMR) and Electrochemical Impedance Spectroscopy (EIS) as well as Molecular Dynamics (MD) simulations were used to study the intermolecular interactions in imidazolium-based IL - water - alkali halide ternary mixtures. The 1H and 23Na 1D and 1H DOSY NMR spectra revealed that the presence of small quantities of NaCl does not influence the aggregation of water molecules in the IL nano-domains. The order of adding ionic compounds to water, as well as the certain water and NaCl molecular ratios, lead to the formation of isolated water clusters. Two ternary solutions representing different orders of compounds mixing (H2O+ IL + NaCl or H2O+ NaCl + IL) showed a strong dependence of the initial solvation shell of Na+ and the self-clustering of water. Furthermore, the behaviour of water was found to be independent from the conditions applied during the solution preparation, such as temperature and/or duration of stirring and aging. These findings could be confirmed by large differences in the amount of ionic species, observed in the ternary solutions and depending on the order of mixing/solute preparation.
Collapse
|
11
|
Gu J, Jia Y, Ren X, Li S, Yan T. The Effects of C2-methylation of Imidazolium-based Ionic Liquid Electrolytes on the Lithium-Ion Transport. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
12
|
Goodwin ZA, Kornyshev AA. Cracking Ion Pairs in the Electrical Double Layer of Ionic Liquids. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.141163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
13
|
Goodwin ZAH, McEldrew MP, de Souza JP, Bazant MZ, Kornyshev AA. Gelation, Clustering and Crowding in the Electrical Double Layer of Ionic Liquids. J Chem Phys 2022; 157:094106. [DOI: 10.1063/5.0097055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Understanding the bulk and interfacial properties of super-concentrated electrolytes, such as ionic liquids (ILs), has attracted significant attention lately for their promising applications in supercapacitors and batteries. Recently, McEldrew et al. developed a theory for reversible ion associations in bulk ILs, which accounted for the formation of all possible Cayley tree clusters and a percolating ionic network (gel). Here we adopt and develop this approach to understand the associations of ILs in the electrical double layer at electrified interfaces. With increasing charge of the electrode, the theory predicts a transition from a regime dominated by a gelled or clustered state to a crowding regime dominated by free ions. This transition from gelation to crowding is conceptually similar to the overscreening to crowding transition.
Collapse
Affiliation(s)
| | - Michael Patrick McEldrew
- Massachusetts Institute of Technology Department of Chemical Engineering, United States of America
| | - J. Pedro de Souza
- MIT, Massachusetts Institute of Technology Department of Chemical Engineering, United States of America
| | | | - Alexei A. Kornyshev
- Department of Chemistry, Imperial College London Faculty of Natural Sciences, United Kingdom
| |
Collapse
|
14
|
Patsahan O, Ciach A. Mesoscopic Inhomogeneities in Concentrated Electrolytes. ACS OMEGA 2022; 7:6655-6664. [PMID: 35252660 PMCID: PMC8892908 DOI: 10.1021/acsomega.1c06013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
A mesoscopic theory for water-in-salt electrolytes combining density functional and field-theoretic methods is developed in order to explain the unexpectedly large period of the oscillatory decay of the disjoining pressure observed in recent experiments for the lithium bis(trifluoromethylsulfonyl)-imide (LiTFSI) salt [T. S. Groves et al., J. Phys. Chem. Lett. 2021, 12, 1702]. We assumed spherical ions with different diameters and implicit solvent, inducing strong, short-range attraction between ions of the same sign. For this highly simplified model, we calculated correlation functions. Our results indicate that mesoscopic inhomogeneities can occur when the sum of the Coulomb and the water-mediated interactions between like ions is attractive at short and repulsive at large distances. We adjusted the attractive part of the potential to the water-in-LiTFSI electrolyte and obtained both the period and the decay rate of the correlations, in semiquantitative agreement with the experiment. In particular, the decay length of the correlations increases nearly linearly with the volume fraction of ions.
Collapse
Affiliation(s)
- Oksana Patsahan
- Institute
for Condensed Matter Physics of the National Academy of Sciences of
Ukraine, Lviv 79011, Ukraine
| | - Alina Ciach
- Institute
of Physical Chemistry, Polish Academy of
Sciences, 01-224 Warszawa, Poland
| |
Collapse
|