title: Polymer-ionic liquid ternary systems for Li-battery electrolytes: Molecular dynamics studies of LiTFSI in a EMIm-TFSI and PEO blend.
abstract: 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(+) coordination and transportation were studied in the ternary electrolyte system, i.e., PEO16LiTFSI⋅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.
authors.affiliation: Instituto de Química-Departamento de Físico-Química, Universidade Federal Fluminense, Outeiro de São João Batista s/n CEP, 24020-150 Niterói, Rio de Janeiro, Brazil.
authors.forename: Luciano T
authors.initials: LT
authors.lastname: Costa
authors.affiliation: Department of Chemistry-Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala, Sweden.
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
authors.affiliation: Department of Chemistry-Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala, Sweden.
authors.forename: Fabian
authors.initials: F
authors.lastname: Jeschull
authors.affiliation: Department of Chemistry-Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Brandell
mesh_terms: D004058:Diffusion; D011211:Electric Power Supplies; D004573:Electrolytes / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D018020:Lithium Compounds / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry*; D013449:Sulfonamides / Q000737:chemistry*; D013696:Temperature
chemical_list: C517865:1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; D004573:Electrolytes; D007093:Imidazoles; D052578:Ionic Liquids; D018020:Lithium Compounds; D013449:Sulfonamides; D011092:Polyethylene Glycols