title: Electrochemical and physicochemical properties of small phosphonium cation ionic liquid electrolytes with high lithium salt content.
abstract: Electrolytes of a room temperature ionic liquid (RTIL), trimethyl(isobutyl)phosphonium (P111i4) bis(fluorosulfonyl)imide (FSI) with a wide range of lithium bis(fluorosulfonyl)imide (LiFSI) salt concentrations (up to 3.8 mol kg(-1) of salt in the RTIL) were characterised using a combination of techniques including viscosity, conductivity, differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), nuclear magnetic resonance (NMR) and cyclic voltammetry (CV). We show that the FSI-based electrolyte containing a high salt concentration (e.g. 1 : 1 salt to IL molar ratio, equivalent to 3.2 mol kg(-1) of LiFSI) displays unusual transport behavior with respect to lithium ion mobility and promising electrochemical behavior, despite an increase in viscosity. These electrolytes could compete with the more traditionally studied nitrogen-based ionic liquids (ILs) in lithium battery applications.
authors.affiliation: Institute for Frontier Materials (IFM), Deakin University, Burwood, Victoria 3125, Australia. patrick.howlett@deakin.edu.au.
authors.forename: G M A
authors.initials: GM
authors.lastname: Girard
authors.forename: M
authors.initials: M
authors.lastname: Hilder
authors.forename: H
authors.initials: H
authors.lastname: Zhu
authors.forename: D
authors.initials: D
authors.lastname: Nucciarone
authors.forename: K
authors.initials: K
authors.lastname: Whitbread
authors.forename: S
authors.initials: S
authors.lastname: Zavorine
authors.forename: M
authors.initials: M
authors.lastname: Moser
authors.forename: M
authors.initials: M
authors.lastname: Forsyth
authors.forename: D R
authors.initials: DR
authors.lastname: MacFarlane
authors.forename: P C
authors.initials: PC
authors.lastname: Howlett