skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Solvate Ionic Liquids at Electrified Interfaces

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(trifluoro-methanesulfonyl)imide ([Li(G3)][TFSI]) sandwiched between electrified surfaces. At negatively charged as well as neutral electrodes, the electrolyte largely maintains the characteristics of SILs, e.g., a majority of the interfacial Li + ions remains coordinated by the 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, e.g., 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 themore » 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 suggest that the 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 SILs electrolytes.« less

Authors:
 [1];  [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [1]
  1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1474513
Alternate Identifier(s):
OSTI ID: 1482436
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 10; Journal Issue: 38; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE

Citation Formats

Yu, Zhou, Fang, Chao, Huang, Jingsong, Sumpter, Bobby G., and Qiao, Rui. Solvate Ionic Liquids at Electrified Interfaces. United States: N. p., 2018. Web. doi:10.1021/acsami.8b10387.
Yu, Zhou, Fang, Chao, Huang, Jingsong, Sumpter, Bobby G., & Qiao, Rui. Solvate Ionic Liquids at Electrified Interfaces. United States. doi:10.1021/acsami.8b10387.
Yu, Zhou, Fang, Chao, Huang, Jingsong, Sumpter, Bobby G., and Qiao, Rui. Wed . "Solvate Ionic Liquids at Electrified Interfaces". United States. doi:10.1021/acsami.8b10387. https://www.osti.gov/servlets/purl/1474513.
@article{osti_1474513,
title = {Solvate Ionic Liquids at Electrified Interfaces},
author = {Yu, Zhou and Fang, Chao and Huang, Jingsong and Sumpter, Bobby G. and Qiao, Rui},
abstractNote = {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(trifluoro-methanesulfonyl)imide ([Li(G3)][TFSI]) sandwiched between electrified surfaces. At negatively charged as well as neutral electrodes, the electrolyte largely maintains the characteristics of SILs, e.g., a majority of the interfacial Li+ ions remains coordinated by the 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, e.g., 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 suggest that the 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 SILs electrolytes.},
doi = {10.1021/acsami.8b10387},
journal = {ACS Applied Materials and Interfaces},
number = 38,
volume = 10,
place = {United States},
year = {2018},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

Figures / Tables:

Figure 1 Figure 1: (a) A schematic of the simulation system composing of a slab of (b) [Li(G3)]+ complex cations and (c) [TFSI]- anions sandwiched between two charged electrodes. In (a), the blue, red, green, and gray spheres denote TFSI-ion, G3 molecule, Li+ ion, and electrode atoms, respectively. In (b-c), the magenta,more » red, gray, white, blue, yellow, and cyan spheres denote the lithium ion, oxygen, carbon, hydrogen, nitrogen, sulfur, and fluorine atoms, respectively. The simulation system, cations, and anions were visualized using the visual molecular dynamics (VMD) package.« less

Save / Share:
Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.