title: Electrolyte Mixtures Based on Ethylene Carbonate and Dimethyl Sulfone for Li-Ion Batteries with Improved Safety Characteristics.
abstract: In this study, novel electrolyte mixtures for Li-ion cells are presented with highly improved safety features. The electrolyte formulations are composed of ethylene carbonate/dimethyl sulfone (80:20 wt/wt) as the solvent mixture and LiBF4 , lithium bis(trifluoromethanesulfonyl)azanide, and lithium bis(oxalato)borate as the conducting salts. Initially, the electrolytes are characterized with regard to their physical properties, their lithium transport properties, and their electrochemical stability. The key advantages of the electrolytes are high flash points of >140 °C, which enhance significantly the intrinsic safety of Li-ion cells containing these electrolytes. This has been quantified by measurements in an accelerating rate calorimeter. By using the newly developed electrolytes, which are liquid down to T=-10 °C, it is possible to achieve C-rates of up to 1.5 C with >80 % of the initial specific capacity. During 100 cycles in cell tests (graphite||LiNi1/3 Co1/3 Mn1/3 O2 ), it is proven that the retention of the specific capacity is >98 % of the third discharge cycle with dependence on the conducting salt. The best electrolyte mixture yields a capacity retention of >96 % after 200 cycles in coin cells.
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Werkstoffkunde, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany). andreas.hofmann2@kit.edu.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hofmann
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Werkstoffkunde, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Matthias
authors.initials: M
authors.lastname: Migeot
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Werkstoffkunde, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Eva
authors.initials: E
authors.lastname: Thißen
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Werkstoffkunde, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Michael
authors.initials: M
authors.lastname: Schulz
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Energiespeichersysteme, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Ralf
authors.initials: R
authors.lastname: Heinzmann
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Energiespeichersysteme, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Sylvio
authors.initials: S
authors.lastname: Indris
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Angewandte Werkstoffphysik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Thomas
authors.initials: T
authors.lastname: Bergfeldt
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Angewandte Werkstoffphysik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Boxia
authors.initials: B
authors.lastname: Lei
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Angewandte Werkstoffphysik, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: Carlos
authors.initials: C
authors.lastname: Ziebert
authors.affiliation: Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien-Werkstoffkunde, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).|Universität Freiburg, Institut für Mikrosystemtechnik, Georges-Köhler-Allee 102, 79110 Freiburg (Germany).
authors.forename: Thomas
authors.initials: T
authors.lastname: Hanemann
mesh_terms: D004058:Diffusion; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D004148:Dioxolanes / Q000737:chemistry*; D004553:Electric Conductivity; D011211:Electric Power Supplies; D004563:Electrochemistry; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D005240:Feasibility Studies; D006358:Hot Temperature; D008094:Lithium / Q000737:chemistry*; D012449:Safety; D013450:Sulfones / Q000737:chemistry*; D014783:Viscosity
chemical_list: D004148:Dioxolanes; D004573:Electrolytes; D013450:Sulfones; D008094:Lithium; C025910:dimethyl sulfone; C031133:ethylene carbonate; D004121:Dimethyl Sulfoxide
keywords: electrochemistry; electrolytes; lithium ion cells; safety; solvent effects