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Philippi F, Middendorf M, Shigenobu K, Matsuyama Y, Palumbo O, Pugh D, Sudoh T, Dokko K, Watanabe M, Schönhoff M, Shinoda W, Ueno K. Evolving better solvate electrolytes for lithium secondary batteries. Chem Sci 2024; 15:7342-7358. [PMID: 38756793 PMCID: PMC11095511 DOI: 10.1039/d4sc01492h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 04/10/2024] [Indexed: 05/18/2024] Open
Abstract
The overall performance of lithium batteries remains unmatched to this date. Decades of optimisation have resulted in long-lasting batteries with high energy density suitable for mobile applications. However, the electrolytes used at present suffer from low lithium transference numbers, which induces concentration polarisation and reduces efficiency of charging and discharging. Here we show how targeted modifications can be used to systematically evolve anion structural motifs which can yield electrolytes with high transference numbers. Using a multidisciplinary combination of theoretical and experimental approaches, we screened a large number of anions. Thus, we identified anions which reach lithium transference numbers around 0.9, surpassing conventional electrolytes. Specifically, we find that nitrile groups have a coordination tendency similar to SO2 and are capable of inducing the formation of Li+ rich clusters. In the bigger picture, we identified a balanced anion/solvent coordination tendency as one of the key design parameters.
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Affiliation(s)
- Frederik Philippi
- Department of Chemistry and Life Science, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
| | | | - Keisuke Shigenobu
- Research Institute for Interdisciplinary Science, Okayama University Okayama 700-8530 Japan
| | - Yuna Matsuyama
- Department of Chemistry and Life Science, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
| | - Oriele Palumbo
- Consiglio Nazionale delle Ricerche Istituto dei Sistemi Complessi, P.le Aldo Moro 5 00185 Rome Italy
| | - David Pugh
- Department of Chemistry, Britannia House, Kings College London 7 Trinity Street London SE1 1DB UK
| | - Taku Sudoh
- Department of Chemistry and Life Science, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
| | - Kaoru Dokko
- Department of Chemistry and Life Science, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
- Advanced Chemical Energy Research Centre, Advanced Institute of Sciences, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
| | - Masayoshi Watanabe
- Advanced Chemical Energy Research Centre, Advanced Institute of Sciences, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
| | | | - Wataru Shinoda
- Research Institute for Interdisciplinary Science, Okayama University Okayama 700-8530 Japan
| | - Kazuhide Ueno
- Department of Chemistry and Life Science, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
- Advanced Chemical Energy Research Centre, Advanced Institute of Sciences, Yokohama National University 79-5 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
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2
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Shimizu K, de Freitas AA, Allred JT, Burba CM. A Computational and Spectroscopic Analysis of Solvate Ionic Liquids Containing Anions with Long and Short Perfluorinated Alkyl Chains. Molecules 2024; 29:2071. [PMID: 38731564 PMCID: PMC11085471 DOI: 10.3390/molecules29092071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 04/22/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024] Open
Abstract
Anion-driven, nanoscale polar-apolar structural organization is investigated in a solvate ionic liquid (SIL) setting by comparing sulfonate-based anions with long and short perfluorinated alkyl chains. Representative SILs are created from 1,2-bis(2-methoxyethoxy)ethane ("triglyme" or "G3"), lithium nonafluoro-1-butanesulfonate, and lithium trifluoromethanesulfonate. Molecular dynamics simulations, density functional theory computations, and vibrational spectroscopy provide insight into the overall liquid structure, cation-solvent interactions, and cation-anion association. Significant competition between G3 and anions for cation-binding sites characterizes the G3-LiC4F9SO3 mixtures. Only 50% of coordinating G3 molecules form tetradentate complexes with Li+ in [(G3)1Li][C4F9SO3]. Moreover, the SIL is characterized by extensive amounts of ion pairing. Based on these observations, [(G3)1Li][C4F9SO3] is classified as a "poor" SIL, similar to the analogous [(G3)1Li][CF3SO3] system. Even though the comparable basicity of the CF3SO3- and C4F9SO3- anions leads to similar SIL classifications, the hydrophobic fluorobutyl groups support extensive apolar domain formation. These apolar moieties permeate throughout [(G3)1Li][C4F9SO3] and persist even at relatively low dilution ratios of [(G3)10Li][C4F9SO3]. By way of comparison, the CF3 group is far too short to sustain polar-apolar segregation. This demonstrates how chemically modifying the anions to include hydrophobic groups can impart unique nanoscale organization to a SIL. Moreover, tuning these nano-segregated fluorinated domains could, in principle, control the presence of dimensionally ordered states in these mixtures without changing the coordination of the lithium ions.
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Affiliation(s)
- Karina Shimizu
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal;
| | - Adilson Alves de Freitas
- Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal;
| | - Jacob T. Allred
- Department of Natural Sciences, Northeastern State University, 611 N Grand Ave., Tahlequah, OK 74464, USA;
| | - Christopher M. Burba
- Department of Natural Sciences, Northeastern State University, 611 N Grand Ave., Tahlequah, OK 74464, USA;
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3
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Nguyen LHB, Picard T, Iojoiu C, Alloin F, Sergent N, Doublet ML, Filhol JS. Investigating the abnormal conductivity behaviour of divalent cations in low dielectric constant tetraglyme-based electrolytes. Phys Chem Chem Phys 2022; 24:21601-21611. [PMID: 36004582 DOI: 10.1039/d2cp03200g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solutions made of tetraglyme (G4) containing Ca(TFSI)2 have been studied as models to understand the solvation structure and the conductivity properties of multivalent ions in low dielectric constant ethereal electrolytes. These solutions have been characterised using electrochemical impedance spectroscopy, rheological measurement, and Raman spectroscopy. The ionic conductivity of these electrolytes shows an intriguing non-monotonic behaviour with temperature which deviates from the semi-empirical Vogel-Tammann-Fulcher equation at a critical temperature. This behaviour is observed for both Mg(TFSI)2 and Ca(TFSI)2, but not LiTFSI, indicating a difference in the solvation structure and the thermodynamic properties of divalent ions compared to Li+. The origin of this peculiar behaviour is demystified using temperature-controlled Raman spectroscopy and first-principles calculations combined with a thermodynamic analysis of the chemical equilibrium of Ca2+ ion-pairing versus solvation. As long-range electrostatic interactions are critical in solutions based on low dielectric ethereal solvents, a periodic approach is here proposed to capture their impact on the solvation structure of the electrolyte at different salt concentrations. The obtained results reveal that the thermodynamic and transport properties of Ca(TFSI)2/G4 solutions stem from a competition between enthalpic (ionic strength) and entropic factors that are directly controlled by the solution concentration and temperature, respectively. At high salt concentrations, the ionic strength of the solution favours the existence of free ions thanks to the strong solvation energy of the polydentate G4 solvent conjugated with the weak complexation ability of TFSI-. At elevated temperatures, the configurational entropy associated with the release of a coordinated G4 favours the formation of contact ion-pairs due to its flat potential energy surface (weak strain energy), offering a large configuration space. Such a balance between ion-pair association and dissociation not only rationalises the ionic conductivity behaviour observed for Ca(TFSI)2/G4 solutions, but also provides valuable information to extrapolate the ionic transport properties of other electrolytes with different M(TFSI)n salts dissolved in longer-chain glymes or even poly(ethylene oxide). These findings are essential for the understanding of solvation structures and ionic transport in low-dielectric media, which can further be used to design new electrolytes for Li-ion and post Li-ion batteries as well as electrocatalysts.
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Affiliation(s)
- Long Hoang Bao Nguyen
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
| | - Tanguy Picard
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000, Grenoble, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
| | - Cristina Iojoiu
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000, Grenoble, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
| | - Fannie Alloin
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000, Grenoble, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
| | - Nicolas Sergent
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000, Grenoble, France.
| | - Marie-Liesse Doublet
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
| | - Jean-Sébastien Filhol
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
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4
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Sudoh T, Shigenobu K, Dokko K, Watanabe M, Ueno K. Li + transference number and dynamic ion correlations in glyme-Li salt solvate ionic liquids diluted with molecular solvents. Phys Chem Chem Phys 2022; 24:14269-14276. [PMID: 35667383 DOI: 10.1039/d2cp01409b] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Highly concentrated electrolytes (HCEs) have attracted significant interest as promising liquid electrolytes for next-generation Li secondary batteries, owing to various beneficial properties both in the bulk and at the electrode/electrolyte interface. One particular class of HCEs consists of binary mixtures of lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and oligoethers that behave like ionic liquids. [Li(G4)][TFSA], which comprises an equimolar mixture of LiTFSA and tetraglyme (G4), is an example. In our previous works, the addition of low-polarity molecular solvents to [Li(G4)][TFSA] was found to effectively enhance the conductivity while retaining the unique Li-ion solvation structure. However, it remains unclear how the diluents affect another key electrolyte parameter-the Li+ transference number-despite its critical importance for achieving the fast charging/discharging of Li secondary batteries. Thus, in this study, the effects of diluents on the extremely low Li+ transference number under anion-blocking conditions in [Li(G4)][TFSA] were elucidated, with a special focus on the polarity of the additional solvents. The concentration dependence of the dynamic ion correlations was further studied in the framework of the concentrated electrolyte theory. The results revealed that a non-coordinating diluent is not involved in the modification of the ion transport mechanism, and therefore the low Li+ transference number is inherited by the diluted electrolytes. In contrast, a coordinating diluent effectively reduces the anti-correlated ion motions of [Li(G4)][TFSA], thereby improving the Li+ transference number. This is the first time that the significant effects of the coordination properties of the diluting solvents on the dynamic ion correlations and Li+ transference numbers have been reported for diluted solvate ionic liquids.
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Affiliation(s)
- Taku Sudoh
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
| | - Keisuke Shigenobu
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
| | - Kaoru Dokko
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan. .,Advanced Chemical Energy Research Centre (ACERC), Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Masayoshi Watanabe
- Advanced Chemical Energy Research Centre (ACERC), Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Kazuhide Ueno
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan. .,Advanced Chemical Energy Research Centre (ACERC), Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
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5
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Watanabe H, Arai N, Han J, Kawana Y, Tsuzuki S, Umebayashi Y. Tools for studying ion solvation and ion pair formation in ionic liquids: isotopic substitution Raman spectroscopy. ANAL SCI 2022; 38:1025-1031. [PMID: 35672500 DOI: 10.1007/s44211-022-00121-7] [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: 02/25/2022] [Accepted: 04/23/2022] [Indexed: 11/01/2022]
Abstract
Isotopic H/D or 6/7Li substitution Raman spectroscopy was applied to new kinds of ionic liquids; N-methylimidazole (C1Im) and acetic acid (CH3COOH) as the pseudo-protic ionic liquid (pPIL), and both of the neat and the 2,2,3,3-tetrafluoropropyl ether (HFE) diluted Li-glyme solvate ionic liquids (SIL) [Li(Gn)][TFSA] (Gn, glyme n = 3 or 4); TFSA, bis(trifluoromethanesulfonyl)amide) to clarify the proton transfer or the Li+ solvation/ion pair formation. The isotopic substitution Raman (ISR) spectra were obtained as the difference between the samples containing the same composition except the substituted isotope. The calculated and theoretical ISR spectra were also evaluated for comparison. With the C1Im-CH3COOH(D) pPIL, the Raman bands attributable to the C1Im/C1HIm+ gave signals of differential shape, and they were well reproduced with the curve fitting by taking the small amount of C1HIm+ and CH3COO- generation into consideration. The ISR spectra for the SIL were well explained by the formation of the Li-TFSA contact ion pair (CIP) and the solvent shared ion pair (SSIP) in the [Li(G3)][TFSA] SIL. In addition, the ISR spectra for the HFE-diluted [Li(G4)][TFSA] SIL clearly proved that the HFE hardly coordinates to the Li+ in the HFE-diluted SIL. Here, the ISR spectroscopy is proposed as a new tool for studying the ion solvation and the ion pair formation in ionic liquids.
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Affiliation(s)
- Hikari Watanabe
- Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Nana Arai
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, 2-no-cho, Nishi-ku, Niigata City, 950-2181, Japan
| | - Jihae Han
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, 2-no-cho, Nishi-ku, Niigata City, 950-2181, Japan
| | - Yui Kawana
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, 2-no-cho, Nishi-ku, Niigata City, 950-2181, Japan
| | - Seiji Tsuzuki
- Japan Advanced Chemical Energy Research Center (ACERC), Institute of Advanced Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan
| | - Yasuhiro Umebayashi
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi, 2-no-cho, Nishi-ku, Niigata City, 950-2181, Japan.
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6
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Ikeda N, Ishikawa A, Fujii K. Polyether-based solid electrolytes with a homogeneous polymer network: effect of the salt concentration on the Li-ion coordination structure. Phys Chem Chem Phys 2022; 24:9626-9633. [PMID: 35403631 DOI: 10.1039/d1cp05351e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report a solid polymer electrolyte with an ideal polyether network that was synthesized by using tetra-functional poly(ethylene glycol) (TetraPEG) and lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) salt. The solid TetraPEG electrolyte had few network defects (<5%) and exhibited high mechanical toughness by enduring approximately 11-fold elongation at a 1 : 10 ratio of Li salt to O atoms of PEG (Li/OPEG). We found that the mechanical properties strongly depend on the Li/OPEG ratio, which mainly contributes to the density of crosslinking points in the electrolyte. Raman spectroscopy and high-energy X-ray total scattering were used with all-atom molecular dynamics simulations to visualize the structural effects of Li-ion coordination in the TetraPEG network. At lower salt contents (Li/OPEG = 1 : 10), Li ions were found to preferentially coordinate with OPEG atoms rather than the TFSA anions to form crown ether-like Li+-PEG complexes as ion pair-free species. With increasing salt content, the TFSA anions partially coordinated with Li ions through O atoms of TFSA (OTFSA) to afford contact ion pairs surrounded by both OPEG and OTFSA atoms. Finally, the ion pairing enhanced mononuclear ion pairs as well as multinuclear ionic aggregates when more Li salt was added. This structural change in the Li-ion complexes was directly reflected by the ion-conducting properties of the electrolyte. The TetraPEG electrolyte composed of the ion pair-free Li+ species (Li/OPEG = 1 : 10) exhibited higher ionic conductivity, and the conductivity gradually decreased with increasing salt content because of extensive ion pairing for both mononuclear contact ion pairs and multinuclear aggregates. Regarding the electrochemical properties, the optimum electrolyte composition to realize a reversible Li deposition/dissolution reaction for a negative electrode was found to be Li/OPEG = 1 : 4.
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Affiliation(s)
- Namie Ikeda
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611, Japan.
| | - Asumi Ishikawa
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611, Japan.
| | - Kenta Fujii
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611, Japan.
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7
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Burba CM, Feightner K, Liu M, Hawari A. The Effect of Fluorinated Solvents on Physicochemical Properties, Ionic Association, and Free Volume of a Prototypical Solvate Ionic Liquid. Chemphyschem 2022; 23:e202100548. [PMID: 34982854 DOI: 10.1002/cphc.202100548] [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: 07/21/2021] [Revised: 01/03/2022] [Indexed: 11/09/2022]
Abstract
Solvate ionic liquid synthesis and properties depend on a delicate balancing of cation-solvent and cation-anion interactions to produce materials containing only cation-solvent complexes and solvent-separated anions. Most SILs meeting these characteristics fall within the paradigm of oligomeric ethylene oxides and lithium salts. Targeted functionalization of solvent molecules to achieve desired properties is a relatively unexplored avenue of research. We explore solvent fluorination for a prototypical SIL based on lithium bis(trifluoromethylsulfonyl)imide (LiNTf2) and triethylene glycol (TEG). In the first experiment, TEG is partially substituted with 2,2,4,4,5,5,7,7-octafluoro-3,6-dioxaoctane-1,8-diol (FTEG). This leads to a decrease in ionic conductivity and proliferation of Li(NTf2)2- species. Both results suggest FTEG does not readily coordinate Li+ ; a conclusion that is reinforced by computational studies of [(TEG)1Li]+ and [(FTEG)1Li]+ cation stabilities. A second experiment adds FTEG as a diluent to [(TEG)1Li]NTf2. This places FTEG and TEG in competition to coordinate a limited number of Li+ ions. The resulting mixtures exhibit conductivity and viscosity enhancements over the parent SIL and minimal changes in ion speciation due to the poor Li+ binding by FTEG. Positron annihilation lifetime spectroscopic studies point to increased amounts of free volume upon dilution of FTEG. This likely explains the origin of the conductivity enhancement.
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Affiliation(s)
- Christopher M Burba
- Northeastern State University, Department of Natural Sciences, 611 N Grand Ave, 74464, Tahlequah, UNITED STATES
| | - Kylie Feightner
- Northeastern State University, Department of Natural Sciences, 611 N Grand Ave, 74464-2302, United States, Tahlequah, UNITED STATES
| | - Ming Liu
- North Carolina State University, Department of Nuclear Engineering, UNITED STATES
| | - Ayman Hawari
- North Carolina State University, Department of Nuclear Engineering, UNITED STATES
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8
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Nguyen LHB, Picard T, Sergent N, Raynaud C, Filhol JS, Doublet ML. Investigation of alkali and alkaline earth solvation structures in tetraglyme solvent. Phys Chem Chem Phys 2021; 23:26120-26129. [PMID: 34559176 DOI: 10.1039/d1cp02939h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This study compares molecular calculations performed with molecular and periodic codes through an investigation of the solvation structures of alkali and alkaline earth metal ions in tetraglyme solution. The two codes are able to produce equivalent structural and energetic information at the same level of theory, and in the presence of the implicit solvation model or not. This comparison reveals that molecular optimisations can be performed with periodic codes and used directly as input models for interface or electrochemistry calculations in order to preserve the solvent-solute interaction and the cavitation energy. By a rigorous comparison, we have demonstrated that equivalent energetic values can be obtained with the conventional PBE-D3 and the newly developed SCAN-rVV10 functionals. Nevertheless, as far as the vibrational features are concerned and when the molecule possesses a highly conjugated system, the SCAN-rVV10 functional is required to describe the vibrational modes properly. The computed IR/Raman spectra can thus be used as essential information to determine the first solvation shell of metal ions in glyme-based solutions. In tetraglyme solution, the alkali and alkaline earth metal ions exhibit a diverse solvation structure. Small ions like Li+ and Mg2+ tend to adopt a coordination number of five or six, while larger ions, Na+, K+, and Ca2+, prefer an eight-coordinated environment, and the metal-ligand interaction increases in the order K+-O < Na+-O < Li+-O < Ca2+-O < Mg2+-O. The solvation spheres play a significant role in the stability and the reactivity of the solvated ions, and can thus be used as input models to construct the solvation structure in more sophisticated electrolytes, such as polyethylene oxide, or perform electrochemical calculations.
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Affiliation(s)
- L H B Nguyen
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France.
| | - T Picard
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000 Grenoble, France
| | - N Sergent
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, LEPMI, 38000 Grenoble, France
| | - C Raynaud
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France.
| | - J-S Filhol
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
| | - M-L Doublet
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France. .,RS2E French Network on Electrochemical Energy Storage, FR5439, Amiens, France
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9
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Watanabe M. Advances in Organic Ionic Materials Based on Ionic Liquids and Polymers. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Masayoshi Watanabe
- Advanced Chemical Energy Research Center, Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan
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10
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Fuladi S, Gholivand H, Ahmadiparidari A, Curtiss LA, Salehi-Khojin A, Khalili-Araghi F. Multicomponent Phase Separation in Ternary Mixture Ionic Liquid Electrolytes. J Phys Chem B 2021; 125:7024-7032. [PMID: 34102840 DOI: 10.1021/acs.jpcb.1c01327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigate the phase behavior of ternary mixtures of ionic liquid, organic solvent, and lithium salt by molecular dynamics simulations. We find that at room temperature, the electrolyte separates into distinct phases with specific compositions; an ion-rich domain that contains a fraction of solvent molecules and a second domain of pure solvent. The phase separation is shown to be entropy-driven and is independent of lithium salt concentration. Phase separation is only observed at microsecond time scales and greatly affects the transport properties of the electrolyte.
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Affiliation(s)
- Shadi Fuladi
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Hamed Gholivand
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Alireza Ahmadiparidari
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Larry A Curtiss
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Amin Salehi-Khojin
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Fatemeh Khalili-Araghi
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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11
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Kimura K, Kiuchi H, Hayashi K, Nakata A, Fujisaki F, Nishio K, Fukunaga T, Matsubara E. Application of Anomalous X-ray Scattering Method to Liquid Electrolytes Used in a Battery: Local Structural Analysis around a Dilute Metallic Ion. Anal Chem 2020; 92:9956-9962. [PMID: 32573217 DOI: 10.1021/acs.analchem.0c01525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In liquid electrolytes used for a battery, various metal complexes are formed as a result of ion-solvent and ion-ion interactions, which strongly influence the properties of the electrolyte and thus the performance of the battery. Therefore, the structural characterization of such complexes is of great importance. In this study, the anomalous X-ray scattering (AXS) technique was applied to the potassium hydroxide solution including ∼0.3 mol % zinc, which is widely used in various batteries such as the alkaline battery. In spite of the small amount of the metallic ions, we have successfully extracted a local structure around zinc after careful data analysis. The obtained pair distribution function exhibited not only the short-range correlation corresponding to the Zn-O bond within the zincate anion but also a medium-range correlation above 3.5 Å. The present study demonstrates the capability of the AXS technique to detect local structures around dilute metallic ions in liquid electrolytes, which will largely extend the applicable range of this technique, especially to the field related to batteries.
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Affiliation(s)
- Koji Kimura
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Nagoya 466-8555, Japan
| | - Hisao Kiuchi
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kouichi Hayashi
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Nagoya 466-8555, Japan.,Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Gokiso, Nagoya 466-8555, Japan
| | - Akiyoshi Nakata
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Fumika Fujisaki
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Koji Nishio
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Toshiharu Fukunaga
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Eiichiro Matsubara
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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12
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Kimura K, Kiuchi H, Morita M, Kawaguchi T, Yoshii K, Sakaebe H, Hayashi K. Development of a half-cell for x-ray structural analysis of liquid electrolytes in rechargeable batteries. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:033907. [PMID: 32260019 DOI: 10.1063/1.5124797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 03/05/2020] [Indexed: 06/11/2023]
Abstract
A half-cell of the rechargeable Li-ion battery was developed to characterize an electrolyte structure using high energy x-ray total scattering measurements in combination with a two-dimensional x-ray detector. The scattering pattern consisted of strong Bragg peaks from electrodes and diffuse scatterings from sapphire windows, in addition to a weak halo pattern from the electrolyte. By selectively removing the signals of the electrodes and windows using specific numerical procedures, we could successfully extract the structural information of the electrolyte, which was in reasonable agreement with the reference data obtained from the electrolyte in a glass capillary. The present demonstration with a half-cell is expected to shed new light on operand characterization of the electrolyte structure during charging and discharging.
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Affiliation(s)
- Koji Kimura
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Hisao Kiuchi
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Masahito Morita
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Tomoya Kawaguchi
- Office of Society-Academia Collaboration for Innovation, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kazuki Yoshii
- Research Institute of Electrochemical Energy (RIECEN), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
| | - Hikari Sakaebe
- Research Institute of Electrochemical Energy (RIECEN), National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
| | - Kouichi Hayashi
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
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13
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Thum A, Heuer A, Shimizu K, Canongia Lopes JN. Solvate ionic liquids based on lithium bis(trifluoromethanesulfonyl)imide–glyme systems: coordination in MD simulations with scaled charges. Phys Chem Chem Phys 2020; 22:525-535. [DOI: 10.1039/c9cp04947a] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Charge scaling in molecular dynamics simulations of lithium bis(trifluoromethanesulfonyl)imide–glyme solvate ionic liquids yields better agreement with experiments.
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Affiliation(s)
- Andreas Thum
- Institut für Physikalische Chemie
- Westfälische Wilhelms-Universität Münster
- 48149 Münster
- Germany
| | - Andreas Heuer
- Institut für Physikalische Chemie
- Westfälische Wilhelms-Universität Münster
- 48149 Münster
- Germany
| | - Karina Shimizu
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049 001 Lisboa
- Portugal
| | - José Nuno Canongia Lopes
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049 001 Lisboa
- Portugal
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14
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Potangale M, Tiwari S. Correlation of the empirical polarity parameters of solvate ionic liquids (SILs) with molecular structure. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.111882] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Ishii Y, Matubayasi N. Self-Consistent Scheme Combining MD and Order- N DFT Methods: An Improved Set of Nonpolarizable Force Fields for Ionic Liquids. J Chem Theory Comput 2019; 16:651-665. [PMID: 31873016 DOI: 10.1021/acs.jctc.9b00793] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nonpolarizable force field of ionic liquids is tuned by using the self-consistent scheme of molecular dynamics (MD) simulation and first-principles calculation based on the order-N density functional theory (DFT). The atomic charges are determined by using the whole MD cell for DFT calculation and accounts effectively for the many-body effects of charge transfer and intramolecular polarization. The charges represent effective interactions in the condensed phase within the framework of the nonpolarizable force field and can be an alternative for an explicitly many-body model incorporating, for example, polarizability. Here we demonstrate the performance of nonpolarizable force field determined with the MD-DFT self-consistent scheme in imidazolium-, pyrrolidinium-, and ammonium-based ionic liquids. The variation ranges of molecular charges are much larger with the compositions of the ionic liquid than with the thermodynamic conditions, and the charge-ordering structures become systematically weaker with the effective charges. For energetic properties, while the calculated heat of vaporization depends on the atomic and molecular charges, the corresponding heat capacity is not strongly affected by the DFT-based variation. For transport properties, the self-diffusion coefficient, electrical conductivity, and viscosity vary much more in the self-consistent scheme. The effective DFT charge is observed to enhance the fluidity of ionic liquids and improve the accuracy of electrical conductivity and viscosity. This is due to the weakened interactions among the ions, and the too slow motions observed with a full-charge model are well corrected through the iteration of MD and DFT. We therefore conclude that the set of nonpolarizable force fields obtained with the MD-DFT self-consistent scheme leads to better description of transport properties of ionic liquids.
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Affiliation(s)
- Yoshiki Ishii
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan.,Elements Strategy Initiative for Catalysts and Batteries , Kyoto University , Katsura , Kyoto 615-8520 , Japan
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16
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Kameda Y, Sato K, Hasebe R, Amo Y, Usuki T, Umebayashi Y, Ikeda K, Otomo T. Solvation Structure of Li + in Methanol and 2-Propanol Solutions Studied by ATR-IR and Neutron Diffraction with 6Li/ 7Li Isotopic Substitution Methods. J Phys Chem B 2019; 123:4967-4975. [PMID: 31094512 DOI: 10.1021/acs.jpcb.9b03477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neutron diffraction measurements have been carried out on 10 mol % LiTFSA (TFSA: bis(trifluoromethylsulfonil)amide) solutions in methanol- d4 and 2-propanol- d8 to obtain information on the solvation structure of Li+. The detailed coordination structure of solvent molecules within the first solvation shell of Li+ was determined through the least-squares fitting analysis of the difference function between normalized scattering cross sections observed for 6Li/7Li isotopically substituted sample solutions. The nearest-neighbor Li+···O distance and coordination number determined for the 10 mol % LiTFSA-methanol- d4 solution are rLiO = 1.98 ± 0.02 Å and nLiO = 3.8 ± 0.6, respectively. In the 2-propanol- d8 solution, it has been revealed that 2-propanol- d8 molecules within the first solvation shell of Li+ take at least two different coordination geometries with the intermolecular nearest-neighbor Li+···O distance of rLiO = 1.93 ± 0.04 Å. The Li+···O coordination number, nLiO = 3.3 ± 0.3, is determined. Ion-pair formation in the LiTFSA-methanol and LiTFSA-2-propanol solutions has been investigated by the attenuated total reflection infrared spectroscopic method. Mole fractions of free, Li+-bound, and aggregated TFSA- are derived from the peak deconvolution analysis of vibrational bands observed for TFSA-.
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Affiliation(s)
- Yasuo Kameda
- Department of Material and Biological Chemistry, Faculty of Science , Yamagata University , Yamagata , Yamagata 990-8560 , Japan
| | - Koichi Sato
- Department of Material and Biological Chemistry, Faculty of Science , Yamagata University , Yamagata , Yamagata 990-8560 , Japan
| | - Ryo Hasebe
- Department of Material and Biological Chemistry, Faculty of Science , Yamagata University , Yamagata , Yamagata 990-8560 , Japan
| | - Yuko Amo
- Department of Material and Biological Chemistry, Faculty of Science , Yamagata University , Yamagata , Yamagata 990-8560 , Japan
| | - Takeshi Usuki
- Department of Material and Biological Chemistry, Faculty of Science , Yamagata University , Yamagata , Yamagata 990-8560 , Japan
| | - Yasuhiro Umebayashi
- Graduate School of Science and Technology , Niigata University , 8050 Ikarashi, 2-no-cho , Nishi-ku, Niigata City 950-2181 , Japan
| | - Kazutaka Ikeda
- Institute of Material Structure Science , KEK , Tsukuba , Ibaraki 305-080 , Japan
| | - Toshiya Otomo
- Institute of Material Structure Science , KEK , Tsukuba , Ibaraki 305-080 , Japan
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17
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Eyckens DJ, Henderson LC. A Review of Solvate Ionic Liquids: Physical Parameters and Synthetic Applications. Front Chem 2019; 7:263. [PMID: 31058138 PMCID: PMC6482472 DOI: 10.3389/fchem.2019.00263] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 04/01/2019] [Indexed: 11/13/2022] Open
Abstract
Solvate Ionic Liquids (SILs) are a relatively new class of ionic liquids consisting of a coordinating solvent and salt, that give rise to a chelate complex with very similar properties to ionic liquids. Herein is the exploration of the reported Kamlet-Taft parameters, Gutmann Acceptor numbers and the investigation of chelating effects through NMR spectroscopy of multiple atomic nuclei. These properties are related to the application of SILs as reaction media for organic reactions. This area is also reviewed here, including the implication in catalysis for the Aldol and Kabachnik-Fields reactions and electrocyclization reactions such as Diels-Alder and [2+2] cycloaddition. Solvate ILs exhibit many interesting properties and hold great potential as a solvent for organic transformations.
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Affiliation(s)
- Daniel J. Eyckens
- Institute for Frontier Materials, Deakin University, Geelong, VIC, Australia
| | - Luke C. Henderson
- Institute for Frontier Materials, Deakin University, Geelong, VIC, Australia
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18
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Watanabe M, Dokko K, Ueno K, Thomas ML. From Ionic Liquids to Solvate Ionic Liquids: Challenges and Opportunities for Next Generation Battery Electrolytes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2018. [DOI: 10.1246/bcsj.20180216] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Masayoshi Watanabe
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan
| | - Kaoru Dokko
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan
| | - Kazuhide Ueno
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan
| | - Morgan L. Thomas
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan
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19
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Sun Y, Hamada I. Insight into the Solvation Structure of Tetraglyme-Based Electrolytes via First-Principles Molecular Dynamics Simulation. J Phys Chem B 2018; 122:10014-10022. [PMID: 30299952 DOI: 10.1021/acs.jpcb.8b07098] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glyme-lithium salt equimolar mixtures, as solvate ionic liquid electrolytes for rechargeable lithium secondary batteries, are of great interest, due to the desirable properties such as high oxidative stability, low vapor pressure, and nonflammability. However, the fundamental understanding of the solvation shell structure in glyme electrolytes has not been clearly established. Herein, we employ first-principles molecular dynamics (FPMD) simulation to study the lithium bis(trifluoromethylsulfonyl)-amide (LiTFSA) and tetraglyme (G4) electrolyte system. For the case of equimolar ratio, a positive correlation between the total coordination number of Li+ ions and the phase stability is clearly established. At the ground state of equimolar LiTFSA-G4 electrolyte, most of the Li+ ions are coordinated to four O atoms of a curled G4 molecule and one O atom of a TFSA- anion, equivalent to the second most stable contact ion pair in gas-phase cluster calculations. By contrast, Li+ ions prefer to be coordinated by two G4 molecules and not in direct contact with TFSA- anions at a low concentration of Li salt. The significantly increased probability of pairing between the Li-G4 complexes and TFSA- anions at the equimolar ratio could be highly relevant to its ionic-liquid-like properties.
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Affiliation(s)
- Yang Sun
- Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN) , National Institute for Materials Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Ikutaro Hamada
- Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN) , National Institute for Materials Science , 1-1 Namiki , Tsukuba 305-0044 , Japan.,Department of Precision Science and Technology, Graduate School of Engineering , Osaka University , 2-1 Yamada-oka , Suita , Osaka 565-0871 , Japan
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20
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Dong D, Bedrov D. Charge Transport in [Li(tetraglyme)][bis(trifluoromethane) sulfonimide] Solvate Ionic Liquids: Insight from Molecular Dynamics Simulations. J Phys Chem B 2018; 122:9994-10004. [PMID: 30299097 DOI: 10.1021/acs.jpcb.8b06913] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Molecular dynamics simulations using fully atomistic polarizable force field have been performed on solvate ionic liquids (SILs), comprised of tetraglyme (G4) solvent molecules, Li+ cations, and bis(trifluoromethane) sulfonimide (TFSI) anions, [Li(G4)][TFSI]. The SILs with equimolar salt:G4 composition were investigated in the 303-373 K temperature range, whereas several systems with lower salt concentrations were investigated at 373 K. The simulations using polarizable force field demonstrate very good consistency of structural and dynamic properties with experimental data. The ability to accurately sample the ion transport mechanisms is particularly encouraging, taking into account that previous simulations employing nonpolarizable models had challenges in sampling dynamics in these systems. Here, we correlate Li+ ion local environment and glyme conformations with dynamic characteristics, such as residence time of species around Li+, self-diffusion coefficients, transference number, and conductivity. The analysis of contributions to Li+ mobility due to changing its local environment (i.e., moving from one glyme/anion to another) and from translational motion of Li+ with its' coordination environment showed significant dominance of the latter. The contributions of cross-ion dynamic correlations to the total conductivity have been quantified, showing strongly positive contribution from the cation-anion anticorrelation. Despite the high degree of Li-TFSI dissociation and positive contribution of the cation-anion anticorrelated motion to conductivity, the Li+ transference numbers for equimolar SILs are very low under the anion blocking conditions.
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Affiliation(s)
- Dengpan Dong
- Department of Materials Science & Engineering , University of Utah , 122 S. Central Campus Drive , Room 304, Salt Lake City , Utah 84112 , United States
| | - Dmitry Bedrov
- Department of Materials Science & Engineering , University of Utah , 122 S. Central Campus Drive , Room 304, Salt Lake City , Utah 84112 , United States
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21
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Wu B, Kuroda K, Takahashi K, Castner EW. Structural analysis of zwitterionic liquids vs. homologous ionic liquids. J Chem Phys 2018; 148:193807. [PMID: 30307210 DOI: 10.1063/1.5010983] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Zwitterionic liquids (Zw-ILs) have been developed that are homologous to monovalent ionic liquids (ILs) and show great promise for controlled dissolution of cellulosic biomass. Using both high energy X-ray scattering and atomistic molecular simulations, this article compares the bulk liquid structural properties for novel Zw-ILs with their homologous ILs. It is shown that the significant localization of the charges on Zw-ILs leads to charge ordering similar to that observed for conventional ionic liquids with monovalent anions and cations. A low-intensity first sharp diffraction peak in the liquid structure factor S(q) is observed for both the Zw-IL and the IL. This is unexpected since both the Zw-IL and IL have a 2-(2-methoxyethoxy)ethyl (diether) functional group on the cationic imidazolium ring and ether functional groups are known to suppress this peak. Detailed analyses show that this intermediate range order in the liquid structure arises for slightly different reasons in the Zw-IL vs. the IL. For the Zw-IL, the ether tails in the liquid are shown to aggregate into nanoscale domains.
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Affiliation(s)
- Boning Wu
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Kosuke Kuroda
- Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Kenji Takahashi
- Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Edward W Castner
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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22
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Shinoda W, Hatanaka Y, Hirakawa M, Okazaki S, Tsuzuki S, Ueno K, Watanabe M. Molecular dynamics study of thermodynamic stability and dynamics of [Li(glyme)] + complex in lithium-glyme solvate ionic liquids. J Chem Phys 2018; 148:193809. [PMID: 30307251 DOI: 10.1063/1.5009814] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Equimolar mixtures of glymes and organic lithium salts are known to produce solvate ionic liquids, in which the stability of the [Li(glyme)]+ complex plays an important role in determining the ionic dynamics. Since these mixtures have attractive physicochemical properties for application as electrolytes, it is important to understand the dependence of the stability of the [Li(glyme)]+ complex on the ion dynamics. A series of microsecond molecular dynamics simulations has been conducted to investigate the dynamic properties of these solvate ionic liquids. Successful solvate ionic liquids with high stability of the [Li(glyme)]+ complex have been shown to have enhanced ion dynamics. Li-glyme pair exchange rarely occurs: its characteristic time is longer than that of ion diffusion by one or two orders of magnitude. Li-glyme pair exchange most likely occurs through cluster formation involving multiple [Li(glyme)]+ pairs. In this process, multiple exchanges likely take place in a concerted manner without the production of energetically unfavorable free glyme or free Li+ ions.
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Affiliation(s)
- Wataru Shinoda
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Yuta Hatanaka
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Masashi Hirakawa
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Susumu Okazaki
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Seiji Tsuzuki
- National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba 305-8568, Japan
| | - Kazuhide Ueno
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Masayoshi Watanabe
- Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
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23
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Yu Z, Fang C, Huang J, Sumpter BG, Qiao R. Solvate Ionic Liquids at Electrified Interfaces. ACS APPLIED MATERIALS & INTERFACES 2018; 10:32151-32161. [PMID: 30156822 DOI: 10.1021/acsami.8b10387] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Solvate ionic liquids (SILs) are a promising electrolyte for Li-ion batteries; thus, their behavior at electrified interfaces is crucial for the operation of these batteries. We report molecular dynamics simulation results for a prototypical SIL of lithium triglyme bis(trifluoromethanesulfonyl)imide ([Li(G3)][TFSI]) sandwiched between electrified surfaces. At negatively charged as well as neutral electrodes, the electrolyte largely maintains the characteristics of SILs in terms of the interfacial Li+ ions' coordination by a similar number of oxygen atoms on G3 ligands as the bulk Li+ ions. The persistence of the complex ions is attributed to the 1:1 Li-G3 ratio in bulk SILs and the fact that G3 molecules readily adapt to the interfacial environment by aligning themselves with the surface to ensure good solvation of the interfacial Li+ ions. Nevertheless, the interfacial Li+ ions also display changes of solvation from that in bulk SIL by deviating from the molecular plane formed by the oxygen atoms on G3 ligands as electrodes become more negatively charged. Using density functional theory along with natural bond orbital calculations, we examine the effects of such structural distortion on the properties of the complex cation. Both the frontier orbital energies of the complex cation and the donor-acceptor interactions between Li+ ions and G3 ligands are found to be dependent on the deviation of Li+ ions from the molecular plane of the G3 ligands, which suggests that the electrochemical reduction of Li+ ions should be facilitated by the structural distortion. These results bear important implications for the nanostructures and properties of SILs near electrified interfaces during actual operations of Li-ion batteries and serve to provide guidance toward the rational design of new SIL electrolytes.
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Affiliation(s)
- Zhou Yu
- Department of Mechanical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Chao Fang
- Department of Mechanical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Jingsong Huang
- Center for Nanophase Materials Sciences and Computational Sciences & Engineering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Bobby G Sumpter
- Center for Nanophase Materials Sciences and Computational Sciences & Engineering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Rui Qiao
- Department of Mechanical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
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24
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Su CC, He M, Amine R, Chen Z, Amine K. Internally Referenced DOSY-NMR: A Novel Analytical Method in Revealing the Solution Structure of Lithium-Ion Battery Electrolytes. J Phys Chem Lett 2018; 9:3714-3719. [PMID: 29901395 DOI: 10.1021/acs.jpclett.8b01359] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A novel methodology is reported on the use of internally referenced diffusion-ordered spectroscopy (IR-DOSY) in divulging the solution structure of lithium-ion battery electrolytes. Toluene was utilized as the internal reference for 1H-DOSY analysis due to its exceptionally low donor number and reasonable solubility in various electrolytes. With the introduction of the internal reference, the solvent coordination ratio of different species in the electrolytes can be easily determined by 1H-DOSY or 7Li-DOSY. This new technique was applied to different carbonate electrolytes, and the results were consistent with a Fourier transform infrared (FTIR) analysis. Compared to conventional vibrational spectroscopy, this IR-DOSY technique avoids the complicated deconvolution of the spectrum and allows determination of the solvent coordination ratio of different species in electrolyte systems with two or more organic solvents.
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Affiliation(s)
- Chi-Cheung Su
- Chemical Sciences and Engineering Division , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Meinan He
- Chemical Sciences and Engineering Division , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Rachid Amine
- Materials Science Division , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Zonghai Chen
- Chemical Sciences and Engineering Division , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
| | - Khalil Amine
- Chemical Sciences and Engineering Division , Argonne National Laboratory , 9700 South Cass Avenue , Argonne , Illinois 60439 , United States
- IRMC, Imam Abdulrahman Bin Faisal University (IAU) , Dammam 34212 , Saudi Arabia
- Material Science and Engineering , Stanford University , Stanford , California 94305 , United States
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25
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Tsurumura T, Tanaka T, Yagi K, Morita M, Kameda Y, Fujii K. Local structures of titanium-ion complexes in redox flow battery electrolytes as revealed by X-ray scattering with difference analysis. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.04.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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26
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Hashimoto K, Suzuki S, Thomas ML, Mandai T, Tsuzuki S, Dokko K, Watanabe M. Magnesium bis(trifluoromethanesulfonyl)amide complexes with triglyme and asymmetric homologues: phase behavior, coordination structures and melting point reduction. Phys Chem Chem Phys 2018; 20:7998-8007. [DOI: 10.1039/c7cp08367j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural and thermal properties of equimolar Mg salt and triglyme/asymmetric homologue mixtures were investigated to decrease the melting point.
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Affiliation(s)
- Kei Hashimoto
- Department of Chemistry and Biotechnology, Yokohama National University
- Yokohama 240-8501
- Japan
| | - Soma Suzuki
- Department of Chemistry and Biotechnology, Yokohama National University
- Yokohama 240-8501
- Japan
| | - Morgan L. Thomas
- Department of Chemistry and Biotechnology, Yokohama National University
- Yokohama 240-8501
- Japan
| | - Toshihiko Mandai
- Faculty of Science and Engineering, Graduate School of Engineering, Iwate University
- Morioka
- Japan
| | - Seiji Tsuzuki
- Research Center for Computational Design of Advanced Functional Materials (CD-FMat), National Institute of Advanced Industrial Science and Technology (AIST)
- Ibaraki 305-8568
- Japan
| | - Kaoru Dokko
- Department of Chemistry and Biotechnology, Yokohama National University
- Yokohama 240-8501
- Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University
- Kyoto 615-8510
| | - Masayoshi Watanabe
- Department of Chemistry and Biotechnology, Yokohama National University
- Yokohama 240-8501
- Japan
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27
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Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex II: Neutron Scattering Instruments. QUANTUM BEAM SCIENCE 2017. [DOI: 10.3390/qubs1030009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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Yamaguchi T, Yoshida K, Yamaguchi T, Kameda Y, Ikeda K, Otomo T. Analysis of Prepeak Structure of Concentrated Organic Lithium Electrolyte by Means of Neutron Diffraction with Isotopic Substitution and Molecular Dynamics Simulation. J Phys Chem B 2017; 121:5355-5362. [PMID: 28485592 DOI: 10.1021/acs.jpcb.7b00686] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The prepeak structure of a 3 mol/kg solution of LiClO4 in propylene carbonate (PC) was studied by both neutron diffraction with isotopic substitution (NDIS) and molecular dynamics (MD) simulation. The NDIS data showed that the intensity of the prepeak decreases experimentally with an increase in the scattering length of the lithium atom from 7Li to 6Li in PC-d6. On the other hand, although the prepeak was observed in solutions of both PC-d6 and PC-h6, it disappears when the 1:1 mixture of PC-d6 and PC-h6 was used as the solvent. The prepeak structure and its variation with the isotope substitution were reproduced well by MD simulation, and they were explained in terms of the contrast of the scattering length densities of the ionic and nonpolar domains.
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Affiliation(s)
- Tsuyoshi Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University , Furo-cho, Chikusa, Nagoya, Aichi 464-8603, Japan
| | - Koji Yoshida
- Department of Chemistry, Faculty of Science, Fukuoka University , Nanakuma, Jonan, Fukuoka 814-0180, Japan
| | - Toshio Yamaguchi
- Department of Chemistry, Faculty of Science, Fukuoka University , Nanakuma, Jonan, Fukuoka 814-0180, Japan
| | - Yasuo Kameda
- Department of Material and Biological Chemistry, Faculty of Science, Yamagata University , 1-4-12, Kojirakawa-machi, Yamagata City, Yamagata 990-8560, Japan
| | - Kazutaka Ikeda
- High Energy Accelerator Research Organization (KEK) , Tsukuba, Ibaraki 305-0801, Japan
| | - Toshiya Otomo
- High Energy Accelerator Research Organization (KEK) , Tsukuba, Ibaraki 305-0801, Japan
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D’Angelo AJ, Panzer MJ. Enhanced Lithium Ion Transport in Poly(ethylene glycol) Diacrylate-Supported Solvate Ionogel Electrolytes via Chemically Cross-linked Ethylene Oxide Pathways. J Phys Chem B 2017; 121:890-895. [DOI: 10.1021/acs.jpcb.6b10125] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anthony J. D’Angelo
- Department of Chemical & Biological Engineering Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Matthew J. Panzer
- Department of Chemical & Biological Engineering Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
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30
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Coles SW, Mishin M, Perkin S, Fedorov MV, Ivaništšev VB. The nanostructure of a lithium glyme solvate ionic liquid at electrified interfaces. Phys Chem Chem Phys 2017; 19:11004-11010. [DOI: 10.1039/c7cp00837f] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lithium glymes adopt a distinct nanostructure at the negative electrode, unlike that observed with conventional ionic liquids.
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Affiliation(s)
| | - Maksim Mishin
- Department of Physics
- Scottish Universities Physics Alliance (SUPA)
- Strathclyde University
- John Anderson Building
- Glasgow G4 0NG
| | - Susan Perkin
- Department of Chemistry
- University of Oxford
- Oxford OX1 3QZ
- UK
| | - Maxim V. Fedorov
- Department of Physics
- Scottish Universities Physics Alliance (SUPA)
- Strathclyde University
- John Anderson Building
- Glasgow G4 0NG
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Tsuzuki S, Mandai T, Suzuki S, Shinoda W, Nakamura T, Morishita T, Ueno K, Seki S, Umebayashi Y, Dokko K, Watanabe M. Effect of the cation on the stability of cation–glyme complexes and their interactions with the [TFSA]− anion. Phys Chem Chem Phys 2017; 19:18262-18272. [DOI: 10.1039/c7cp02779f] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interactions of glymes with alkali or alkaline earth metal cations depend strongly on the metal cations.
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