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Karatrantos AV, Middendorf M, Nosov DR, Cai Q, Westermann S, Hoffmann K, Nürnberg P, Shaplov AS, Schönhoff M. Diffusion and structure of propylene carbonate-metal salt electrolyte solutions for post-lithium-ion batteries: From experiment to simulation. J Chem Phys 2024; 161:054502. [PMID: 39087537 DOI: 10.1063/5.0216222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 07/11/2024] [Indexed: 08/02/2024] Open
Abstract
The diffusion of cations in organic solvent solutions is important for the performance of metal-ion batteries. In this article, pulsed field gradient nuclear magnetic resonance experiments and fully atomistic molecular dynamic simulations were employed to study the temperature-dependent diffusive behavior of various liquid electrolytes representing 1M propylene carbonate solutions of metal salts with bis(trifluoromethylsulfonyl)imide (TFSI-) or hexafluorophosphate (PF6-) anions commonly used in lithium-ion batteries and beyond. The experimental studies revealed the temperature dependence of the diffusion coefficients for the propylene carbonate (PC) solvent and for the anions following an Arrhenius type of behavior. It was observed that the PC molecules are the faster species. For the monovalent cations (Li+, Na+, K+), the PC solvent diffusion was enhanced as the cation size increased, while for the divalent cations (Mg2+, Ca2+, Sr2+, Ba2+), the opposite trend was observed, i.e., the diffusion coefficients decreased as the cation size increased. The anion diffusion in LiTFSI and NaTFSI solutions was found to be similar, while in electrolytes with divalent cations, a decrease in anion diffusion with increasing cation size was observed. It was shown that non-polarizable charge-scaled force fields could correspond perfectly to the experimental values of the anion and PC solvent diffusion coefficients in salt solutions of both monovalent (Li+, Na+, K+) and divalent (Mg2+, Ca2+, Sr2+, Ba2+) cations at a range of operational temperatures. Finally, after calculating the radial distribution functions between cations, anions, and solvent molecules, the increase in the PC diffusion coefficient established with the increase in cation size for monovalent cations was clearly explained by the large hydration shell of small Li+ cations, due to their strong interaction with the PC solvent. In solutions with larger monovalent cations, such as Na+, and with a smaller solvation shell of PC, the PC diffusion is faster due to more liberated solvent molecules. In the salt solutions with divalent cations, both the anion and the PC diffusion coefficients decreased as the cation size increased due to an enhanced cation-anion coordination, which was accompanied by an increase in the amount of PC in the cation solvation shell due to the presence of anions.
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Affiliation(s)
- Argyrios V Karatrantos
- Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg
- School of Chemistry and Chemical Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7EX, United Kingdom
| | - Maleen Middendorf
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
- International Graduate School on Battery Chemistry, Characterization, Analysis, Recycling and Application (BACCARA), Münster, Germany
| | - Daniil R Nosov
- Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg
- Department of Physics and Materials Science, University of Luxembourg, 2 Avenue de l'Université, L-4365 Esch-sur-Alzette, Luxembourg
| | - Qiong Cai
- School of Chemistry and Chemical Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7EX, United Kingdom
| | - Stephan Westermann
- Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg
| | - Katja Hoffmann
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Pinchas Nürnberg
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Alexander S Shaplov
- Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg
| | - Monika Schönhoff
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
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Kondou S, Sakashita Y, Yang X, Hashimoto K, Dokko K, Watanabe M, Ueno K. Li-Ion Transport and Solvation of a Li Salt of Weakly Coordinating Polyanions in Ethylene Carbonate/Dimethyl Carbonate Mixtures. ACS APPLIED MATERIALS & INTERFACES 2022; 14:18324-18334. [PMID: 35426656 DOI: 10.1021/acsami.1c25067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Electrolytes with a high Li-ion transference number (tLi) have attracted significant attention for the improvement of the rapid charge-discharge performance of Li-ion batteries (LIBs). Nonaqueous polyelectrolyte solutions exhibit high tLi upon immobilization of the anion on a polymer backbone. However, the transport properties and Li-ion solvation in these media are not fully understood. Here, we investigated the Li salt of a weakly coordinating polyanion, poly[(4-styrenesulfonyl)(trifluoromethanesulfonyl)amide] (poly(LiSTFSA)), in various ethylene carbonate and dimethyl carbonate mixtures. The highest ionic conductivity was unexpectedly observed for the lowest polar mixture at the highest salt concentration despite the low dissociation degree of poly(LiSTFSA). This was attributed to a unique conduction phenomenon resulting from the faster diffusion of transiently solvated Li ions along the interconnected aggregates of polyanion chains. A Li/LiFePO4 cell using such an electrolyte demonstrated improved rate capability. These results provide insights into a design strategy of nonaqueous liquid electrolytes for LIBs.
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Affiliation(s)
- Shinji Kondou
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Yusuke Sakashita
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Xiaoxiao Yang
- Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Kei Hashimoto
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, 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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Liu M, Chimtali PJ, Huang XB, Zhang RB. Structures and dynamic properties of the LiPF 6 electrolytic solution under electric fields - a theoretical study. Phys Chem Chem Phys 2019; 21:13186-13193. [PMID: 31172997 DOI: 10.1039/c9cp00561g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorinated carbonates have attracted increasing attention in high-voltage lithium ion battery applications. Under free and electric fields, their structure-related solvent dynamic properties such as charge and discharge rate, however, are rarely reported. Herein, solutions including linear fluorinated carbonates have been simulated using joint MD/DFT calculations. For the first time, the dielectric constants of the four pure fluorinated carbonates have been predicted to be ca. 5.4 (4: ethyl-2,2,2-trifluoroethyl carbonate)-12.1 (7: di-1,1,2,2,2-pentafluoroethyl carbonate), which are dependent on the number of fluorine atoms. Minor difference in the solvation free energies and few contact ion associations were observed in the ETFEC and DTFEC solvents. Their comparable viscosity values were found through calculations of ion diffusivity and conductivity. In the electric fields, the Li+ mobilities in the two solutions have similar values, showing that the dynamic properties of the electrolytic solutions are almost independent of the number of fluorine atoms on these carbonates. There emerges an oriented and ordered arrangement of the solvent molecules and thus the largely decreased dielectric constants under the electric fields, even though the field strength is very low. These interesting phenomena should be relevant in the formation of contact and aggregate ion pairs, leading to unexpected reduction of the charge-discharge rate-related ion mobility in mixed solvents.
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Affiliation(s)
- Man Liu
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, South Street No. 5, Zhongguancun, Haidian District, 100081 Beijing, China.
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Karatrantos A, Khan S, Ohba T, Cai Q. The effect of different organic solvents on sodium ion storage in carbon nanopores. Phys Chem Chem Phys 2018; 20:6307-6315. [DOI: 10.1039/c7cp04878e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
GCMC atomistic simulation to study the coupled effects of nanoporous hard carbon and different organic solvents on Na ion storage.
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Affiliation(s)
- Argyrios Karatrantos
- Department of Chemical and Process Engineering
- University of Surrey
- Guildford GU2 7XH
- UK
- Luxembourg Institute of Science and Technology
| | - Sharif Khan
- Graduate School of Science
- Chiba University
- Inage
- Japan
| | - Tomonori Ohba
- Graduate School of Science
- Chiba University
- Inage
- Japan
| | - Qiong Cai
- Department of Chemical and Process Engineering
- University of Surrey
- Guildford GU2 7XH
- UK
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