Polymer-ionic liquid ternary systems for Li-battery electrolytes: Molecular dynamics studies of LiTFSI in a EMIm-TFSI and PEO blend

Journal Article · Tue Jul 14 00:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4926470· OSTI ID:22490908

Sun, Bing; Jeschull, Fabian; Brandell, Daniel ^[1]

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1. Department of Chemistry—Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala (Sweden)

This paper presents atomistic molecular dynamics simulation studies of lithium bis(trifluoromethane)sulfonylimide (LiTFSI) in a blend of 1-ethyl-3-methylimidazolium (EMIm)-TFSI and poly(ethylene oxide) (PEO), which is a promising electrolyte material for Li- and Li-ion batteries. Simulations of 100 ns were performed for temperatures between 303 K and 423 K, for a Li:ether oxygen ratio of 1:16, and for PEO chains with 26 EO repeating units. Li{sup +} coordination and transportation were studied in the ternary electrolyte system, i.e., PEO{sub 16}LiTFSI⋅1.0 EMImTFSI, by applying three different force field models and are here compared to relevant simulation and experimental data. The force fields generated significantly different results, where a scaled charge model displayed the most reasonable comparisons with previous work and overall consistency. It is generally seen that the Li cations are primarily coordinated to polymer chains and less coupled to TFSI anion. The addition of EMImTFSI in the electrolyte system enhances Li diffusion, associated to the enhanced TFSI dynamics observed when increasing the overall TFSI anion concentration in the polymer matrix.

• OSTI ID: 22490908
• Journal Information: Journal of Chemical Physics, Vol. 143, Issue 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
97 MATHEMATICAL METHODS AND COMPUTING
ANIONS
CATIONS
COMPARATIVE EVALUATIONS
CONCENTRATION RATIO
DIFFUSION
ELECTROLYTES
EXPERIMENTAL DATA
LITHIUM
LITHIUM ION BATTERIES
LITHIUM IONS
MOLECULAR DYNAMICS METHOD
MOLTEN SALTS
OXYGEN
POLYETHYLENE GLYCOLS
SIMULATION