Electrolyte Solvation and Ionic Association III. Acetonitrile-Lithium Salt Mixtures–Transport Properties

Seo, Daniel M.; Borodin, Oleg; Balogh, Dániel; O’Connell, Michael J.; Ly, Quang; Han, Sang‐Don; Passerini, Stefano; Henderson, Wesley A.

doi:10.1149/2.018308jes

Cited by 152 publications

(227 citation statements)

References 53 publications

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“…Here this implies that the Na + -PC based electrolytes remain liquid for higher concentrations and lower temperatures than the Li + -ACN based electrolytes. This is partially supported by the liquid ranges of 1.0 M NaPF6-PC, remaining liquid down to -95 °C [54], and 1.0 M LiPF6-ACN, crystallizing already at room temperature [30]. In this sense, the analysis of the CN variance represents a tool to link the local molecular picture obtained from quantum mechanical computations with macro-scale battery relevant electrolyte properties.…”

Section: Practical Consequences For Battery Usagementioning

confidence: 83%

“…These ensembles were made with a racemic mixture of R-PC and S-PC. The explored molar ratios approximately correspond to 1.0-5.0 M for ACN [30], and for PC ca. …”

Section: Computationalmentioning

confidence: 87%

“…For these systems the Li + based electrolytes are expected to have higher conductivities than the Na + based electrolytes due to a denser and likely smaller solvation shell (hence diffusing faster). In contrast, MD simulations show that the extensive ion-ion interactions present for higher salt concentrations promote electrolyte structures that resemble polymeric highly viscous networks, where cations have short residence times at their coordination sites [30,44]. Under such conditions the ionic conductivity might follow a Grotthuss-like transport mechanism, where cations move via a sequential series of jumps between neighbouring sites and the ionic conductivity is decoupled from the viscosity [23,24,52].…”

Section: Practical Consequences For Battery Usagementioning

confidence: 97%

“…Molecular dynamics (MD) simulations have been used to generate a large amount of configurations, thus allowing statistics on solvates as functions of salt concentration and anion type and linking these to phase behaviour [27,28] and transport properties [30]. However, the (classical) force fields used may fail in providing a proper description of highly concentrated electrolytes as the interactions become very nonstandard.…”

Section: Introductionmentioning

confidence: 99%

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Solvation structure in dilute to highly concentrated electrolytes for lithium-ion and sodium-ion batteries

Flores

Åvall

Jeschke

et al. 2017

Electrochimica Acta

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The solvation structure of several lithium and sodium based electrolytes are explored as a function of salt concentration over a wide range via a detailed PM7 computational study.The cation coordination shells are found to be well-defined and solvent rich for dilute electrolytes, while disordered and anion rich for the more concentrated electrolytes. The Nabased electrolytes display larger cation coordination shells with a more pronounced presence of fluorine as compared to the Li-based electrolytes. The origins of the structural differences are discussed as well as their consequences for properties of battery electrolytes and battery usage -especially targeting the current large interest in highly concentrated electrolytes.

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Section: Practical Consequences For Battery Usagementioning

confidence: 83%

“…These ensembles were made with a racemic mixture of R-PC and S-PC. The explored molar ratios approximately correspond to 1.0-5.0 M for ACN [30], and for PC ca. …”

Section: Computationalmentioning

confidence: 87%

Section: Practical Consequences For Battery Usagementioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Solvation structure in dilute to highly concentrated electrolytes for lithium-ion and sodium-ion batteries

Flores

Åvall

Jeschke

et al. 2017

Electrochimica Acta

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“…Li + cation coordination (i.e., ionic association interactions) is a prominent feature of solvate formation, were found to have a much lower ionic conductivity than electrolytes with more weakly coordinating anions (e.g., PF 6 − and ClO 4 − ). 3 This is as one might expect once the ionic association tendency of the salts is well understood, but the details of why the conductivity values are low are missing.…”

mentioning

confidence: 80%

Electrolyte Solvation and Ionic Association

Borodin

Han

Daubert

et al. 2015

J. Electrochem. Soc.

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Molecular dynamics (MD) simulations of acetonitrile (AN) mixtures with LiBF 4 , LiCF 3 SO 3 and LiCF 3 CO 2 provide extensive details about the molecular-and mesoscale-level solution interactions and thus explanations as to why these electrolytes have very different thermal phase behavior and electrochemical/physicochemical properties. The simulation results are in full accord with a previous experimental study of these (AN) n -LiX electrolytes. This computational study reveals how the structure of the anions strongly influences the ionic association tendency of the ions, the manner in which the aggregate solvates assemble in solution and the length of time in which the anions remain coordinated to the Li + cations in the solvates which result in dramatic variations in the transport properties of the electrolytes. Understanding the origin of the widely varying transport properties (e.g., viscosity, ionic conductivity and diffusion coefficients) of battery electrolytes remains a key challenge. The present work continues a detailed study into the solution structure of electrolytes-ion solvation and ionic association interactions-to provide mechanistic explanations for electrolyte properties. Previous manuscripts have examined in detail acetonitrile electrolytes with numerous lithium salts: (AN) n -LiX. [1][2][3][4][5][6] Electrolytes with the most strongly associated anions studied (i.e., CF 3 SO 3 − and CF 3 CO 2 − ), in which anion. . . Li + cation coordination (i.e., ionic association interactions) is a prominent feature of solvate formation, were found to have a much lower ionic conductivity than electrolytes with more weakly coordinating anions (e.g., PF 6 − and ClO 4 − ). 3 This is as one might expect once the ionic association tendency of the salts is well understood, but the details of why the conductivity values are low are missing.Two particularly notable points from the previous studies are that:(1) The average solvation numbers, obtained from a Raman spectroscopic analysis, for the (AN) n -LiCF 3 CO 2 solutions were found to be almost constant near a value of 1 (i.e., one AN molecule per Li + cation) over a wide concentration range, even for very dilute solutions. It remains unclear, however, as to why such electrolytes have such a low degree of solvation and why highly concentrated (>5 M) liquid electrolytes-perhaps contrary to expectations-can be prepared with LiCF 3 CO 2 with this being the case.(2) Experimental measurements of the solution structure and transport properties of (AN) n -LiCF 3 SO 3 mixtures were unobtainable due to the rapid crystallization of a solid solvate phase (i.e., (AN) 1 :LiCF 3 SO 3 ) from the electrolytes. 1 Liquid electrolytes with this salt can, however, be readily studied using molecular dynamics (MD) simulations to better understand how and why solution interactions differ for differing anions.The present work therefore delves deeper into the molecular-and mesoscale-level interactions using MD simulations applied to the characterization of (AN) n -LiCF 3 SO 3 and -LiCF ...

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Scavenging Materials to Stabilize LiPF₆‐Containing Carbonate‐Based Electrolytes for Li‐Ion Batteries

et al. 2018

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In conjunction with electrolyte additives used for tuning the interfacial structures of electrodes, functional materials that eliminate or deactivate reactive substances generated by the degradation of LiPF6‐containing electrolytes in lithium‐ion batteries offer a wide range of electrolyte formulation opportunities. Herein, the recent advancements in the development of: (i) scavengers with high selectivity and affinity toward unwanted species and (ii) promoters of ion‐paired LiPF6 dissociation are highlighted, showing that the utilization of the above additives can effectively mitigate the problem of electrolyte instability that commonly results in battery performance degradation and lifetime shortening. A deep mechanistic understanding of LiPF6‐containing electrolyte failure and the action of currently developed additives is demonstrated to enable the rational design of effective scavenging materials and thus allow the fabrication of highly reliable batteries.

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Electrolyte Solvation and Ionic Association III. Acetonitrile-Lithium Salt Mixtures–Transport Properties

Cited by 152 publications

References 53 publications

Solvation structure in dilute to highly concentrated electrolytes for lithium-ion and sodium-ion batteries

Solvation structure in dilute to highly concentrated electrolytes for lithium-ion and sodium-ion batteries

Electrolyte Solvation and Ionic Association

Scavenging Materials to Stabilize LiPF₆‐Containing Carbonate‐Based Electrolytes for Li‐Ion Batteries

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Electrolyte Solvation and Ionic Association III. Acetonitrile-Lithium Salt Mixtures–Transport Properties

Cited by 152 publications

References 53 publications

Solvation structure in dilute to highly concentrated electrolytes for lithium-ion and sodium-ion batteries

Solvation structure in dilute to highly concentrated electrolytes for lithium-ion and sodium-ion batteries

Electrolyte Solvation and Ionic Association

Scavenging Materials to Stabilize LiPF6‐Containing Carbonate‐Based Electrolytes for Li‐Ion Batteries

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Product

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Scavenging Materials to Stabilize LiPF₆‐Containing Carbonate‐Based Electrolytes for Li‐Ion Batteries