1
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Deshmukh SH, Nachaki EO, Kuroda DG. Uncovering the binding nature of thiocyanate in contact ion pairs with lithium ions. J Chem Phys 2024; 161:034507. [PMID: 39017430 DOI: 10.1063/5.0216491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 06/28/2024] [Indexed: 07/18/2024] Open
Abstract
Ion pair formation is a fundamental molecular process that occurs in a wide variety of systems, including electrolytes, biological systems, and materials. In solution, the thiocyanate (SCN-) anion interacts with cations to form contact ion pairs (CIPs). Due to its ambidentate nature, thiocyanate can bind through either its sulfur or nitrogen atoms, depending on the solvent. This study focuses on the binding nature of thiocyanate with lithium ions as a function of the solvents using FTIR, 2D infrared spectroscopy (2DIR) spectroscopies, and theoretical calculations. The study reveals that the SCN- binding mode (S or N end) in CIPs can be identified through 2DIR spectroscopy but not by linear IR spectroscopy. Linear IR spectroscopy shows that the CN stretch frequencies are too close to one another to separate N- and S-bound CIPs. Moreover, the IR spectrum shows that the S-C stretch presents different frequencies for the salt in different solvents, but it is related to the anion speciation rather than to its binding mode. A similar trend is observed for the anion bend. 2DIR spectra show different dynamics for N-bound and S-bound thiocyanate. In particular, the frequency-frequency correlation function (FFCF) dynamics extracted from the 2DIR spectra have a single picosecond exponential decay for N-bound thiocyanate and a biexponential decay for S-bound thiocyanate, consistent with the binding mode of the anion. Finally, it is also observed that the binding mode also affects the line shape parameters, probably due to the different molecular mechanisms of the FFCF for N- and S-bound CIPs.
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Affiliation(s)
- Samadhan H Deshmukh
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Ernest O Nachaki
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Daniel G Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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2
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Nachaki E, Kuroda DG. Transitioning from Regular Electrolytes to Solvate Ionic Liquids to High-Concentration Electrolytes: Changes in Transport Properties and Ionic Speciation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:11522-11533. [PMID: 39050925 PMCID: PMC11264273 DOI: 10.1021/acs.jpcc.4c02248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 06/18/2024] [Accepted: 07/03/2024] [Indexed: 07/27/2024]
Abstract
Glyme-based lithium-ion electrolytes have received considerable attention from the scientific community due to their improved safety, as well as electrochemical and thermal stability over carbonate-based electrolytes. However, these electrolytes suffer from major drawbacks such as high viscosities. To overcome the challenges that hinder their full potential, the molecular description of glyme-based lithium electrolytes in the high-concentration regime, particularly in the solvate ionic liquid (SIL) and high-concentration electrolyte (HCE) regimes, is needed. In this study, model glyme-based electrolytes based on a lithium thiocyanate and either tetraglyme (G4) or a mixture of monoglyme (G1) and diglyme (G2) were investigated as a function of the solvent-to-lithium ratio using linear and nonlinear IR spectroscopies, in combination with ab initio computations as well as electrochemical methods . The transport properties reveal enhanced ionicities in the HCE and SIL regimes ([O]/[Li] ≤ 5) compared to the regular electrolytes (REs, with [O]/[Li] > 5) in both pure (G4) and mixed (G1:G2) glymes. IR and ab initio computations relate these larger ionicities to the higher concentration of charged aggregates in the HCE and SIL electrolytes ([O]/[Li] ≤ 5). Moreover, it was observed that the use of mixed glymes appears to have a minimal effect on the transport properties of REs but exhibits deleterious effects on SILs. Overall, the results provide a molecular framework for describing the local structure of lithium glyme-based electrolytes and demonstrate the key role that the nature of glyme solvation plays in the molecular structure and consequently the macroscopic properties of the Li-glyme SILs, HCEs, and REs.
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Affiliation(s)
- Ernest
O. Nachaki
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Daniel G. Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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3
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Nachaki E, Kuroda DG. Lithium ion Speciation in Cyclic Solvents: Impact of Anion Charge Delocalization and Solvent Polarizability. J Phys Chem B 2024; 128:3408-3415. [PMID: 38546442 PMCID: PMC11017243 DOI: 10.1021/acs.jpcb.3c06872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/12/2024]
Abstract
The increasing demand for lithium batteries has triggered the search for safer and more efficient electrolytes. Insights into the atomistic description of electrolytes are critical for relating microscopic and macroscopic (physicochemical) properties. Previous studies have shown that the type of lithium salt and solvent used in the electrolyte influences its performance by dictating the speciation of the ionic components in the system. Here, we investigate the molecular origins of ion association in lithium-based electrolytes as a function of anion charge delocalization and solvent chemical identity. To this end, a family of cyano-based lithium salts in organic solvents, having a cyclic structure and containing carbonyl groups, was investigated using a combination of linear infrared spectroscopy and ab initio computations. Our results show that the formation of contact-ion pairs (CIPs) is more favorable in organic solvents containing either ester or carbonate groups and in lithium salts with an anion having low charge delocalization than in an amide/urea solvent and an anion with large charge delocalization. Ab initio computations attribute the degree of CIP formation to the energetics of the process, which is largely influenced by the chemical nature of the lithium ion solvation shell. At the molecular level, atomic charge analysis reveals that CIP formation is directly related to the ability of the solvent molecule to rearrange its electronic density upon coordination to the lithium ion. Overall, these findings emphasize the importance of local interactions in determining the nature of ion-molecule interactions and provide a molecular framework for explaining lithium ion speciation in the design of new electrolytes.
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Affiliation(s)
- Ernest
O. Nachaki
- Department of Chemistry, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
| | - Daniel G. Kuroda
- Department of Chemistry, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
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4
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Butreddy P, Wijesingha M, Laws S, Pathiraja G, Mo Y, Rathnayake H. Insight into the Isoreticularity of Li-MOFs for the Design of Low-Density Solid and Quasi-Solid Electrolytes. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:9857-9878. [PMID: 38107191 PMCID: PMC10720344 DOI: 10.1021/acs.chemmater.3c01021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 12/19/2023]
Abstract
Isoreticularity in metal organic frameworks (MOFs) allows the design of the framework structure and tailoring the pore aperture at the molecular level. The optimal pore volume, long-range order of framework expansion, and crystallite size (grain size) could enable improving Li-ion conduction, thereby providing a unique opportunity to design high-performance solid and quasi-solid electrolytes. However, definitive understanding of the pore aperture, framework expansion, and crystallite size on the Li-ion conduction and its mechanism in MOFs remains at the exploratory stage. Among the different MOF subfamilies, Li-MOFs created by the isoreticular framework expansion using dicarboxylates of benzene, naphthalene, and biphenyl building blocks emerge as low-density porous solids with exceptional thermal stability to study the solid-state Li+ transport mechanisms. Herein, we report the subtle effect of the isoreticularity in Li-MOFs on the performance of solid and quasi-solid-state Li+ conduction, providing new insight into Li+ transport mechanisms in MOFs for the first time. Our experimental and computational results show that the reticular design on an isostructural extended framework structure with the optimal pore aperture and crystallite size can influence the Li+ conductivity, exhibiting comparable ionic conductivities to solid polymer electrolytes at room temperature. Aligning with the computational studies, our experimental absorption spectral traces of solid electrolytes prepared by encapsulating lithium salt (LiClO4) and the plasticizer (ethylene carbonate) with Li-MOFs confirm the participation of the free and bound states of Li+ in a pore filling-driven ion conduction mechanism. We postulate that porous channels of Li-MOFs aid free Li+ to move through the pores via a vehicle-type mechanism, in which the pore-filled plasticizer acts as a carrier for mobile Li+ while the framework's functional sites transport the bound state of Li+ via an ion hopping mechanism from one crystallite site to another. Our computational studies performed on the Li+ conduction pathway validated the postulated pore filling mechanism and confirmed the involvement of bridging complexes, formed by binding Li+ onto the framework's functional sites as well as to the pore-filled ethylene carbonates. The Li+ diffusion energy barrier profiles along with the respective conformational changes during the diffusion of Li+ in solid electrolytes prepared from Li-BDC MOF and Li-NDC MOF strongly support the cooperative movement of Li+ ions via ion hopping along the framework's edges and vehicle-type transfer, involving the pore-filled plasticizer. Our findings suggest that cooperative function of the optimal pore volume, framework expansion, and crystallite size play a unique role in Li-ion conduction, thereby providing design guidelines for the low-density solid and quasi-solid electrolytes.
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Affiliation(s)
- Pravalika Butreddy
- Department of Nanoscience,
Joint School of Nanoscience & Nanoengineering, University of North Carolina at Greensboro, 1907 East Gate City Blvd, Greensboro, North Carolina 27401, United States
| | - Manoj Wijesingha
- Department of Nanoscience,
Joint School of Nanoscience & Nanoengineering, University of North Carolina at Greensboro, 1907 East Gate City Blvd, Greensboro, North Carolina 27401, United States
| | - Selina Laws
- Department of Nanoscience,
Joint School of Nanoscience & Nanoengineering, University of North Carolina at Greensboro, 1907 East Gate City Blvd, Greensboro, North Carolina 27401, United States
| | - Gayani Pathiraja
- Department of Nanoscience,
Joint School of Nanoscience & Nanoengineering, University of North Carolina at Greensboro, 1907 East Gate City Blvd, Greensboro, North Carolina 27401, United States
| | - Yirong Mo
- Department of Nanoscience,
Joint School of Nanoscience & Nanoengineering, University of North Carolina at Greensboro, 1907 East Gate City Blvd, Greensboro, North Carolina 27401, United States
| | - Hemali Rathnayake
- Department of Nanoscience,
Joint School of Nanoscience & Nanoengineering, University of North Carolina at Greensboro, 1907 East Gate City Blvd, Greensboro, North Carolina 27401, United States
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5
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Huang Z, Li X, Chen Z, Li P, Ji X, Zhi C. Anion chemistry in energy storage devices. Nat Rev Chem 2023; 7:616-631. [PMID: 37316580 DOI: 10.1038/s41570-023-00506-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2023] [Indexed: 06/16/2023]
Abstract
Anions serve as an essential component of electrolytes, whose effects have long been ignored. However, since the 2010s, we have seen a considerable increase of anion chemistry research in a range of energy storage devices, and it is now understood that anions can be well tuned to effectively improve the electrochemical performance of such devices in many aspects. In this Review, we discuss the roles of anion chemistry across various energy storage devices and clarify the correlations between anion properties and their performance indexes. We highlight the effects of anions on surface and interface chemistry, mass transfer kinetics and solvation sheath structure. Finally, we conclude with a perspective on the challenges and opportunities of anion chemistry for enhancing specific capacity, output voltage, cycling stability and anti-self-discharge ability of energy storage devices.
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Affiliation(s)
- Zhaodong Huang
- Hong Kong Center for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong SAR, China
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Xinliang Li
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, China
| | - Ze Chen
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Pei Li
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Xiulei Ji
- Department of Chemistry, Oregon State University, Corvallis, OR, USA.
| | - Chunyi Zhi
- Hong Kong Center for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong SAR, China.
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China.
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6
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Biswas A, Mallik BS. Direct Correlation between Short-Range Vibrational Spectral Diffusion and Localized Ion-Cage Dynamics of Water-in-Salt Electrolytes. J Phys Chem B 2023; 127:236-248. [PMID: 36575973 DOI: 10.1021/acs.jpcb.2c04391] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The molecular dynamics simulations of a "water-in-salt" electrolyte, lithium bis(trifluoromethyl sulfonyl) imide (LiNTf2), with a varying concentration range of 3 to 20 m were performed to establish a direct connection between a dynamic property like the ion-cage lifetime with the short-range vibrational stretching frequency shift of the used probe, HOD. The properties reported here are compared to that obtained from experiments performed at the same concentrations. The time-series wavelet transform was adopted as a preferable mathematical tool for calculating the instantaneous fluctuating frequencies of the probe O-D stretch mode and the concentration-dependent vibrational stretch spectral signature based on the variable functions associated with a particular chemical bond derived from classical molecular dynamics trajectories. The decay time constants of frequency fluctuations and the lifetime of the ion cage (τIC) were estimated as a function of salt concentration. Herein, we emphasize the correlation between the slowest time constant (τ3) of the decay of O-D stretch frequency fluctuations and the timescales associated with the lifetime of ion cages (τIC). The results exhibit that the existing relationships were also concentration-dependent. Therefore, this study highlights the connection between the ionic motions that regulate the overall system dynamics with the short-range vibrational frequency shift of the used probe, which was used similar to experiments. It also provides an understanding of the interionic interactions and the dynamical and spectral properties of the electrolytic mixtures. We establish a direct correlation between short-range frequency profile and localized ion-cage lifetime, which can fill the gap of understanding between viscosity, vibrational frequency, and ion-cage dynamics of electrolytes.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
| | - Bhabani S Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
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7
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Green M, Kaydanik K, Orozco M, Hanna L, Marple MAT, Fessler KAS, Jones WB, Stavila V, Ward PA, Teprovich JA. Closo-Borate Gel Polymer Electrolyte with Remarkable Electrochemical Stability and a Wide Operating Temperature Window. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2106032. [PMID: 35393776 PMCID: PMC9165492 DOI: 10.1002/advs.202106032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/14/2022] [Indexed: 06/01/2023]
Abstract
A major challenge in the pursuit of higher-energy-density lithium batteries for carbon-neutral-mobility is electrolyte compatibility with a lithium metal electrode. This study demonstrates the robust and stable nature of a closo-borate based gel polymer electrolyte (GPE), which enables outstanding electrochemical stability and capacity retention upon extensive cycling. The GPE developed herein has an ionic conductivity of 7.3 × 10-4 S cm-2 at room temperature and stability over a wide temperature range from -35 to 80 °C with a high lithium transference number ( t Li + $t_{{\rm{Li}}}^ + $ = 0.51). Multinuclear nuclear magnetic resonance and Fourier transform infrared are used to understand the solvation environment and interaction between the GPE components. Density functional theory calculations are leveraged to gain additional insight into the coordination environment and support spectroscopic interpretations. The GPE is also established to be a suitable electrolyte for extended cycling with four different active electrode materials when paired with a lithium metal electrode. The GPE can also be incorporated into a flexible battery that is capable of being cut and still functional. The incorporation of a closo-borate into a gel polymer matrix represents a new direction for enhancing the electrochemical and physical properties of this class of materials.
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Affiliation(s)
- Matthew Green
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
| | - Katty Kaydanik
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
| | - Miguel Orozco
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
| | - Lauren Hanna
- Advanced Manufacturing and Energy Science, Savannah River National Laboratory, Aiken, SC, 29803, USA
| | - Maxwell A T Marple
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94551, USA
| | | | - Willis B Jones
- Spectroscopy Separations and Material Characterization, Savannah River National Laboratory, Aiken, SC, 29803, USA
| | - Vitalie Stavila
- Energy Nanomaterials, Sandia National Laboratory, Livermore, CA, 94551, USA
| | - Patrick A Ward
- Advanced Manufacturing and Energy Science, Savannah River National Laboratory, Aiken, SC, 29803, USA
| | - Joseph A Teprovich
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
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8
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Lim C, Kim JH, Chae Y, Lee KK, Kwak K, Cho M. Solvation Structure around Li + Ions in Organic Carbonate Electrolytes: Spacer-Free Thin Cell IR Spectroscopy. Anal Chem 2021; 93:12594-12601. [PMID: 34491717 DOI: 10.1021/acs.analchem.1c02127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Organic carbonate electrolytes are widely used materials for lithium-ion batteries. However, detailed solvation structures and solvent coordination numbers (CNs) of lithium cations in such solutions have not been accurately described nor determined yet. Because transmission-type IR spectroscopy is not of use for measuring the carbonyl stretch modes of electrolytes due to their absorption saturation problem, we here show that simple spacer-free thin cell IR spectroscopy can provide quantitative information on the number of solvating carbonate molecules around each lithium ion. We could estimate the solvent (carbonate) CNs of lithium ions in dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, and butylene carbonate over a wide range of lithium salt concentrations accurately, and they are compared with the previous results obtained with attenuated total reflection IR spectroscopy technique. We anticipate that our spacer-free thin cell approach will potentially be used to investigate the solvation dynamics, chemical exchange process, and vibrational energy transfers between solvating carbonate molecules in lithium salt electrolytes when combined with time-resolved IR spectroscopy.
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Affiliation(s)
- Chaiho Lim
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea.,Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Joo Hyun Kim
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea.,Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Yeongseok Chae
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Kyung-Koo Lee
- Department of Chemistry, Kunsan National University, Gunsan 54150, Republic of Korea
| | - Kyungwon Kwak
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea.,Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
| | - Minhaeng Cho
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Republic of Korea.,Department of Chemistry, Korea University, Seoul 02841, Republic of Korea
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9
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Fulfer KD, Galle Kankanamge SR, Chen X, Woodard KT, Kuroda DG. Elucidating the mechanism behind the infrared spectral features and dynamics observed in the carbonyl stretch region of organic carbonates interacting with lithium ions. J Chem Phys 2021; 154:234504. [PMID: 34241245 DOI: 10.1063/5.0049742] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ultrafast infrared spectroscopy has become a very important tool for studying the structure and ultrafast dynamics in solution. In particular, it has been recently applied to investigate the molecular interactions and motions of lithium salts in organic carbonates. However, there has been a discrepancy in the molecular interpretation of the spectral features and dynamics derived from these spectroscopies. Hence, the mechanism behind spectral features appearing in the carbonyl stretching region was further investigated using linear and nonlinear spectroscopic tools and the co-solvent dilution strategy. Lithium perchlorate in a binary mixture of dimethyl carbonate (DMC) and tetrahydrofuran was used as part of the dilution strategy to identify the changes of the spectral features with the number of carbonates in the first solvation shell since both solvents have similar interaction energetics with the lithium ion. Experiments showed that more than one carbonate is always participating in the lithium ion solvation structures, even at the low concentration of DMC. Moreover, temperature-dependent study revealed that the exchange of the solvent molecules coordinating the lithium ion is not thermally accessible at room temperature. Furthermore, time-resolved IR experiments confirmed the presence of vibrationally coupled carbonyl stretches among coordinated DMC molecules and demonstrated that this process is significantly altered by limiting the number of carbonate molecules in the lithium ion solvation shell. Overall, the presented experimental findings strongly support the vibrational energy transfer as the mechanism behind the off-diagonal features appearing on the 2DIR spectra of solutions of lithium salt in organic carbonates.
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Affiliation(s)
- Kristen D Fulfer
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | | | - Xiaobing Chen
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Kaylee T Woodard
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Daniel G Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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10
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Zhang X, Chen X, Kuroda DG. Computing the frequency fluctuation dynamics of highly coupled vibrational transitions using neural networks. J Chem Phys 2021; 154:164514. [PMID: 33940799 DOI: 10.1063/5.0044911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The description of frequency fluctuations for highly coupled vibrational transitions has been a challenging problem in physical chemistry. In particular, the complexity of their vibrational Hamiltonian does not allow us to directly derive the time evolution of vibrational frequencies for these systems. In this paper, we present a new approach to this problem by exploiting the artificial neural network to describe the vibrational frequencies without relying on the deconstruction of the vibrational Hamiltonian. To this end, we first explored the use of the methodology to predict the frequency fluctuations of the amide I mode of N-methylacetamide in water. The results show good performance compared with the previous experimental and theoretical results. In the second part, the neural network approach is used to investigate the frequency fluctuations of the highly coupled carbonyl stretch modes for the organic carbonates in the solvation shell of the lithium ion. In this case, the frequency fluctuation predicted by the neural networks shows a good agreement with the experimental results, which suggests that this model can be used to describe the dynamics of the frequency in highly coupled transitions.
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Affiliation(s)
- Xiaoliu Zhang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Xiaobing Chen
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Daniel G Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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11
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Computational insight into the structural properties and redox chemistry of poly (ethylene carbonate) as electrolytes for Lithium batteries. J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2021.114995] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Bezabh HK, Tsai MC, Hagos TT, Beyene TT, Berhe GB, Hagos TM, Abrha LH, Chiu SF, Su WN, Hwang BJ. Roles of film-forming additives in diluted and concentrated electrolytes for lithium metal batteries: A density functional theory-based approach. Electrochem commun 2020. [DOI: 10.1016/j.elecom.2020.106685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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13
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Galle Kankanamge SR, Kuroda DG. Molecular Structure, Chemical Exchange, and Conductivity Mechanism of High Concentration LiTFSI Electrolytes. J Phys Chem B 2020; 124:1965-1977. [PMID: 32069048 PMCID: PMC7307920 DOI: 10.1021/acs.jpcb.9b10795] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
High
concentration lithium electrolytes have been found to be good
candidates for high energy density and high voltage lithium batteries.
Recent studies have shown that limiting the free solvent molecules
in the electrolytes prevents the degradation of the battery electrodes.
However, the molecular level knowledge of the structure and dynamics
of such an electrolyte system is limited, especially for electrolytes
based on typical organic carbonates. In this article, the interactions
and motions involved in lithium bis(trifluoromethanesulfonyl)imide
in carbonyl-containing solvents are investigated using linear and
time-resolved vibrational spectroscopies and computational methods.
Our results suggest that the overall structure and the speciation
of the three high concentration electrolytes are similar. However,
the cyclic carbonate-based electrolyte presents an additional interaction
as a result of dimer formation. Time-resolved studies reveal similar
and fast dynamics for the structural motions of solvent molecules
in electrolytes composed of linear molecules, while the electrolyte
made of cyclic solvent molecules shows slower structural changes as
a result of the dimer formation. Additionally, a picosecond time scale
process is observed and assigned to the coordination and decoordination
of solvent molecules from a lithium-ion solvation shell. This process
of solvent exchange is found to be directly correlated to the making
and breaking of structures between the lithium-ion and the anion and,
consequently, to the conduction mechanism. Overall, our data show
that the molecular structure of the solvent does not significantly
affect the speciation and distribution of the lithium-ion solvation
shells. However, the presence of dimerization between solvent molecules
of two neighboring lithium-ions appears to produce a microscopic ordering
that it is manifested macroscopically in properties of the electrolyte,
such as its viscosity.
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Affiliation(s)
| | - Daniel G Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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14
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Voropaeva D, Novikova S, Xu T, Yaroslavtsev A. Polymer Electrolytes for LIBs Based on Perfluorinated Sulfocationic Nepem-117 Membrane and Aprotic Solvents. J Phys Chem B 2019; 123:10217-10223. [PMID: 31689107 DOI: 10.1021/acs.jpcb.9b08555] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polymer electrolytes have been obtained by using Nepem-117 membranes in a Li+ form intercalated by polar aprotic solvents, such as dimethylformamide, dimethyl sulfoxide (DMSO), and dimethylacetamide (DMA), and solvent mixtures, such as ethylene carbonate-propylene carbonate (EC-PC), EC-DMA, EC-PC-DMA, and EC-PC-DMA-tetrahydrofuran. The obtained electrolytes have been characterized by IR impedance and 7Li pulsed field gradient NMR spectroscopy. Ion mobility was observed to increase with higher degrees of solvation of the membranes. A method is demonstrated to determine the solvent uptake corresponding to the percolation threshold. With comparable solvent uptake, materials containing a solvent with a higher permittivity and a lower viscosity have higher values of ionic conductivity. The membranes containing the three-component mixture of EC-PC-DMA show the highest ionic conductivity values (8.1 and 2.1 mS/cm at 25 and -20 °C, respectively). Such values exceed the conductivity of electrolytes on the basis of the Nafion membranes solvated with aprotic solvents.
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Affiliation(s)
- Daria Voropaeva
- Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences , 31 Leninsky prospect , Moscow 119991 , Russia.,Institute of Problems of Chemical Physics of Russian Academy of Sciences , Academician Semenov avenue 1 , Chernogolovka 142432 , Russia
| | - Svetlana Novikova
- Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences , 31 Leninsky prospect , Moscow 119991 , Russia
| | - Tongwen Xu
- School of Chemistry and Material Science , University of Science and Technology of China , Hefei 230026 , P. R. China
| | - Andrey Yaroslavtsev
- Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences , 31 Leninsky prospect , Moscow 119991 , Russia.,Institute of Problems of Chemical Physics of Russian Academy of Sciences , Academician Semenov avenue 1 , Chernogolovka 142432 , Russia.,National Research University Higher School of Economics , Moscow 101000 , Russia
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15
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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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16
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Zhang X, Kuroda DG. An ab initio molecular dynamics study of the solvation structure and ultrafast dynamics of lithium salts in organic carbonates: A comparison between linear and cyclic carbonates. J Chem Phys 2019; 150:184501. [DOI: 10.1063/1.5088820] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Xiaoliu Zhang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Daniel G. Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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17
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Jiang H, Zhang Q, Zhang Y, Sui L, Wu G, Yuan K, Yang X. Li-Ion solvation in propylene carbonate electrolytes determined by molecular rotational measurements. Phys Chem Chem Phys 2019; 21:10417-10422. [DOI: 10.1039/c8cp07552b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the solvation structure of Li+ in LiPF6–PC solutions using ultrafast vibrational spectroscopy. The results illustrate the salt concentration-dependent solvation structures, in accordance with the variation of ion conductivity.
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Affiliation(s)
- Haotian Jiang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Qi Zhang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Yutong Zhang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Laizhi Sui
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
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18
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Tulibaeva GZ, Shestakov AF, Volkov VI, Yarmolenko OV. Structure of LiBF4 Solvate Complexes in Ethylene Carbonate, Based on High-Resolution NMR and Quantum-Chemical Data. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2018. [DOI: 10.1134/s0036024418040313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Deng GH, Shen Y, He Z, Zhang Q, Jiang B, Yuan K, Wu G, Yang X. The molecular rotational motion of liquid ethanol studied by ultrafast time resolved infrared spectroscopy. Phys Chem Chem Phys 2018; 19:4345-4351. [PMID: 28119958 DOI: 10.1039/c6cp07380h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this report, ultrafast time-resolved infrared spectroscopy is used to study the rotational motion of the liquid ethanol molecule. The results showed that the methyl, methylene, and CO groups have close rotational relaxation times, 1-2 ps, and the rotational relaxation time of the hydroxyl group (-OH) is 8.1 ps. The fast motion of the methyl, methylene and CO groups, and the slow motion of the hydroxyl group suggested that the ethanol molecules experience anisotropic motion in the liquid phase. The slow motion of the hydroxyl group also shows that the hydrogen bonded network could be considered as an effective molecule. The experimental data provided in this report are helpful for theorists to build models to understand the molecular rotational motion of liquid ethanol. Furthermore, our experimental method, which can provide more data concerning the rotational motion of sub groups of liquid molecules, will be useful for understanding the complicated molecular motion in the liquid phase.
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Affiliation(s)
- Gang-Hua Deng
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
| | - Yuneng Shen
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China. and Tongji Zhejiang College, Jiaxing 314000, Zhejiang, China
| | - Zhigang He
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
| | - Qiang Zhang
- Institute of Chemistry & Chemical Engineering, Bohai University, Jinzhou 121000, China
| | - Bo Jiang
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
| | - Kaijun Yuan
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
| | - Guorong Wu
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
| | - Xueming Yang
- State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
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20
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Unger I, Seidel R, Thürmer S, Pohl MN, Aziz EF, Cederbaum LS, Muchová E, Slavíček P, Winter B, Kryzhevoi NV. Observation of electron-transfer-mediated decay in aqueous solution. Nat Chem 2017. [DOI: 10.1038/nchem.2727] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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