Abstract
Lithium-ion transport is significantly retarded in ionic liquids (ILs). In this work, we performed extensive molecular dynamics simulations to mimic the kinetics of lithium ions in ILs using [N-methyl-N-propylpyrrolidium (pyr\(_{13}\))][bis(trifluoromethanesulfonyl)imide (Ntf\(_{2}\))] with added LiNtf\(_{2}\) salt. And we analyzed their transport, developing a two-state model and comparing it to the machine learning-identified states. The transport of lithium ions involves local shell exchanges of the Ntf\(_{2}\) in the medium. We calculated train size distributions over various time scales. The train size distribution decays as a power law, representing non-Poissonian bursty shell exchanges. We analyzed the non-Poissonian processes of lithium ions transport as a two-state (soft and hard) model. We analytically calculated the transition probability of the two-state model, which fits well to the lifetime autocorrelation functions of LiNtf\(_{2}\) shells. To identify two states, we introduced the graph neutral network incorporating local molecular structure. The results reveal that the shell-soft state mainly contributes to the transport of the lithium ions, and their contribution is more important in low temperatures. Hence, it is the key for enhanced lithium ion transport to increase the fraction of the shell-soft state.
Graphical abstract
Similar content being viewed by others
Data availability
This manuscript has associated data in a data repository. [Authors’ comment: The authors will provide data on reasonable request.]
References
N. Molinari, J.P. Mailoa, B. Kozinsky, General trend of a negative li effective charge in ionic liquid electrolytes. J. Phys. Chem. Lett. 10(10), 2313–2319 (2019). https://doi.org/10.1021/acs.jpclett.9b00798
N. Molinari, J.P. Mailoa, N. Craig, J. Christensen, B. Kozinsky, Transport anomalies emerging from strong correlation in ionic liquid electrolytes. J. Power Sources 428, 27–36 (2019). https://doi.org/10.1016/j.jpowsour.2019.04.085
M. McEldrew, Z.A.H. Goodwin, N. Molinari, B. Kozinsky, A.A. Kornyshev, M.Z. Bazant, Salt-in-ionic-liquid electrolytes: ion network formation and negative effective charges of alkali metal cations. J. Phys. Chem. B 125(50), 13752–13766 (2021). https://doi.org/10.1021/acs.jpcb.1c05546. (PMID: 34902256)
M. McEldrew, Z.A.H. Goodwin, S. Bi, M.Z. Bazant, A.A. Kornyshev, Theory of ion aggregation and gelation in super-concentrated electrolytes. J. Chem. Phys. 152(23), 234506 (2020). https://doi.org/10.1063/5.0006197
M. McEldrew, Z.A.H. Goodwin, H. Zhao, M.Z. Bazant, A.A. Kornyshev, Correlated ion transport and the gel phase in room temperature ionic liquids. J. Phys. Chem. B 125(10), 2677–2689 (2021). https://doi.org/10.1021/acs.jpcb.0c09050. (PMID: 33689352)
Z.A.H. Goodwin, M. McEldrew, B. Kozinsky, M.Z. Bazant, Theory of cation solvation and ionic association in nonaqueous solvent mixtures. PRX Energy 2, 013007 (2023). https://doi.org/10.1103/PRXEnergy.2.013007
C. Fang, D.M. Halat, N.P. Balsara, R. Wang, Dynamic heterogeneity of solvent motion and ion transport in concentrated electrolytes. J. Phys. Chem. B 127(8), 1803–1810 (2023). https://doi.org/10.1021/acs.jpcb.2c08029. (PMID: 36800550)
A. Choudhary, D. Dong, D. Bedrov, Li+ transport in ethylene carbonate based comb-branched solid polymer electrolyte: a molecular dynamics simulation study. ACS Appl. Polym. Mater. 4(11), 8496–8507 (2022). https://doi.org/10.1021/acsapm.2c01416
D. Dong, D. Bedrov, Charge transport in [li(tetraglyme)][bis(trifluoromethane) sulfonimide] solvate ionic liquids: Insight from molecular dynamics simulations. J. Phys. Chem. B 122(43), 9994–10004 (2018). https://doi.org/10.1021/acs.jpcb.8b06913. (PMID: 30299097)
Z. Li, O. Borodin, G.D. Smith, D. Bedrov, Effect of organic solvents on li+ ion solvation and transport in ionic liquid electrolytes: A molecular dynamics simulation study. J. Phys. Chem. B 119, 3085–3096 (2015). https://doi.org/10.1021/jp510644k
V. Lesch, Z. Li, D. Bedrov, O. Borodin, A. Heuer, The influence of cations on lithium ion coordination and transport in ionic liquid electrolytes: A md simulation study. Phys. Chem. Chem. Phys. 18, 382–392 (2016). https://doi.org/10.1039/c5cp05111h
J.B. Haskins, W.R. Bennett, J.J. Wu, D.M. Hernández, O. Borodin, J.D. Monk, C.W. Bauschlicher, J.W. Lawson, Computational and experimental investigation of li-doped ionic liquid electrolytes: [pyr14][tfsi], [pyr13][fsi], and [emim][bf4]. J. Phys. Chem. B 118, 11295–11309 (2014). https://doi.org/10.1021/jp5061705
Z. Li, G.D. Smith, D. Bedrov, Li+ solvation and transport properties in ionic liquid/lithium salt mixtures: a molecular dynamics simulation study. J. Phys. Chem. B 116, 12801–12809 (2012). https://doi.org/10.1021/jp3052246
Z. Li, O. Borodin, G.D. Smith, D. Bedrov, Effect of organic solvents on li+ ion solvation and transport in ionic liquid electrolytes: a molecular dynamics simulation study. J. Phys. Chem. B 119(7), 3085–3096 (2015). https://doi.org/10.1021/jp510644k. (PMID: 25592777)
J.B. Haskins, W.R. Bennett, J.J. Wu, D.M. Hernández, O. Borodin, J.D. Monk, C.W.J. Bauschlicher, J.W. Lawson, Computational and experimental investigation of li-doped ionic liquid electrolytes: [pyr14][tfsi], [pyr13][fsi], and [emim][bf4]. J. Phys. Chem. B 118(38), 11295–11309 (2014). https://doi.org/10.1021/jp5061705. (PMID: 25159701)
D.M. Seo, O. Borodin, D. Balogh, M. O’Connell, Q. Ly, S.-D. Han, S. Passerini, W.A. Henderson, Electrolyte solvation and ionic association III. Acetonitrile–lithium salt mixtures-transport properties. J. Electrochem. Soc. 160(8), 1061 (2013). https://doi.org/10.1149/2.018308jes
L. Kahle, A. Musaelian, N. Marzari, B. Kozinsky, Unsupervised landmark analysis for jump detection in molecular dynamics simulations. Phys. Rev. Mater. 3, 055404 (2019). https://doi.org/10.1103/PhysRevMaterials.3.055404
N. Molinari, Y. Xie, I. Leifer, A. Marcolongo, M. Kornbluth, B. Kozinsky, Spectral denoising for accelerated analysis of correlated ionic transport. Phys. Rev. Lett. 127, 025901 (2021). https://doi.org/10.1103/PhysRevLett.127.025901
V. Bapst, T. Keck, A. Grabska-Barwińska, C. Donner, E.D. Cubuk, S.S. Schoenholz, A. Obika, A.W.R. Nelson, T. Back, D. Hassabis, P. Kohli, Unveiling the predictive power of static structure in glassy systems. Nat. Phys. 16, 448–454 (2020). https://doi.org/10.1038/s41567-020-0842-8
N.N. Rajput, V. Murugesan, Y. Shin, K.S. Han, K.C. Lau, J. Chen, J. Liu, L.A. Curtiss, K.T. Mueller, K.A. Persson, Elucidating the solvation structure and dynamics of lithium polysulfides resulting from competitive salt and solvent interactions. Chem. Mater. 29, 3375–3379 (2017). https://doi.org/10.1021/acs.chemmater.7b00068
C. Schröder, Comparing reduced partial charge models with polarizable simulations of ionic liquids. Phys. Chem. Chem. Phys. 14, 3089–3102 (2012). https://doi.org/10.1039/c2cp23329k
I. Pethes, A comparison of classical interatomic potentials applied to highly concentrated aqueous lithium chloride solutions. J. Mol. Liq. 242, 845–858 (2017). https://doi.org/10.1016/j.molliq.2017.07.076
T. Köddermann, D. Paschek, R. Ludwig, Molecular dynamic simulations of ionic liquids: A reliable description of structure, thermodynamics and dynamics. ChemPhysChem 8, 2464–2470 (2007). https://doi.org/10.1002/cphc.200700552
O. Borodin, G.D. Smith, W. Henderson, Li+ cation environment, transport, and mechanical properties of the litfsi doped n-methyl-n-alkylpyrrolidinium+tfsi- ionic liquids. J. Phys. Chem. B 110, 16879–16886 (2006). https://doi.org/10.1021/jp061930t
L. Martinez, R. Andrade, E.G. Birgin, J.M. Martínez, Packmol: a package for building initial configurations for molecular dynamics simulations. J. Comput. Chem. 30, 2157–2164 (2009). https://doi.org/10.1002/jcc.21224
O. Borodin, Polarizable force field development and molecular dynamics simulations of ionic liquids. J. Phys. Chem. B 113, 11463–11478 (2009). https://doi.org/10.1021/jp905220k
G.J. Martyna, D.J. Tobias, M.L. Klein, Constant pressure molecular dynamics algorithms. J. Chem. Phys. 101, 4177–4189 (1994). https://doi.org/10.1063/1.467468
O. Borodin, G.D. Smith, Mechanism of ion transport in amorphous poly(ethylene oxide)/litfsi from molecular dynamics simulations. Macromolecules 39(4), 1620–1629 (2006). https://doi.org/10.1021/ma052277v
O. Borodin, G.D. Smith, P. Fan, Molecular dynamics simulations of lithium alkyl carbonates. J. Phys. Chem. B 110(45), 22773–22779 (2006). https://doi.org/10.1021/jp0639142. (PMID: 17092027)
O. Borodin, G.V. Zhuang, P.N. Ross, K. Xu, Molecular dynamics simulations and experimental study of lithium ion transport in dilithium ethylene dicarbonate. J. Phys. Chem. C 117(15), 7433–7444 (2013). https://doi.org/10.1021/jp4000494
M. Karsai, H.-H. Jo, K. Kaski et al., Bursty Human Dynamics (Springer, Cham, 2018)
G. Feng, M. Chen, S. Bi, Z.A.H. Goodwin, E.B. Postnikov, N. Brilliantov, M. Urbakh, A.A. Kornyshev, Free and bound states of ions in ionic liquids, conductivity, and underscreening paradox. Phys. Rev. X (2019). https://doi.org/10.1103/PhysRevX.9.021024
Github repository for the GNNs. https://github.com/deepmind/deepmind-research.git
Webpage for the GNNs by Google Deepmind. https://www.deepmind.com/blog/towards-understanding-glasses-with-graph-neural-networks
Acknowledgements
This research was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) 2018M3D1A1058624, 2021R1A2C1014562, and 2022R1A4A1030660.
Author information
Authors and Affiliations
Contributions
YSJ and WBL designed the project. YSJ and YKL developed the theoretical formula and performed numerical calculations. YKL, JBC, and JSK performed simulations. YSJ, YKL, JBC, and WBL analyzed data and wrote the manuscript.
Corresponding authors
Additional information
Festschrift in honor of Philip (Fyl) Pincus. Guest editors: Jean-Marc Di Meglio, David Andelman, Cyrus R. Safinya Dedication: “We dedicate this article to Fyl Pincus, our lifelong mentor and a pioneer in the field of soft matter. His research, leadership, and guidance have inspired many scientists, including us.”.
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Lee, Y., Cho, J., Kim, J. et al. Anomalous diffusion of lithium-anion clusters in ionic liquids. Eur. Phys. J. E 46, 105 (2023). https://doi.org/10.1140/epje/s10189-023-00365-9
Received:
Accepted:
Published:
DOI: https://doi.org/10.1140/epje/s10189-023-00365-9