Impact of polyethyleneglycol addition on diffusion coefficients in binary ionic liquid electrolytes composed of dicationic ionic liquid and polyethyleneglycol

2018 
We conduct a comparative study of conductivity and diffusion coefficient of two dicationic ionic liquids (3,3'-(octane-1,8-diyl)bis(1-ethyl-3-imidazolium) bis(trifluoromethylsulfonyl)amide ([IMCI][TFSI], S1) and 3,3'-(2,2'-(ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(1-ethyl-3-imidazolium) bis(trifluoromethylsulfonyl)amide ([IMOI][TFSI], S2)) at various temperatures. The diffusion coefficients of cation and anion in ionic liquids (ILs) are determined using pulse gradient spin-echo nuclear magnetic resonance (PGSE-NMR) method. S2 shows lower viscosity, higher conductivity, and higher diffusion coefficient than those of S1. Moreover, the influence of polyethyleneglycol (PEG200, Mw = 200) addition in PEG200/IL binary solutions is investigated. PEG200/S1 binary solutions show lower viscosity, higher conductivity, and higher diffusion coefficient than those of neat S1. The experimental molar conductivity (Λ) of neat IL and PEG200/IL binary solutions are lower than those of the calculated molar conductivity (ΛNMR) from PGSE NMR method at various temperatures, indicating that not all the diffusion species belong to the ionic conduction. In other words, NMR diffusion measurements comprise charged and paired (without charge) ions.
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    36
    References
    3
    Citations
    NaN
    KQI
    []