  Among the distinctive structural features of lithium ionic liquids (LILs), a
novel class of single-component electrolytes, the variation of the
electron-withdrawing group stands out as a key factor in determining their
dynamics. To understand this phenomenon, we conducted molecular dynamics (MD)
simulations for LILs based on hexafluoro-2-propanoxy (LIL2),
hexafluoro-2-methyl-2-propanoxy (LIL4), and trifluoro-2-propanoxy (LIL6)
derivatives. Results revealed that correlated ion dynamics govern the general
transport characteristics in LILs, while the electron-withdrawing group
regulates the Li transport mechanism. Upon saturation by fluorine atoms, LILs
exhibit higher inhomogeneity in their transport and structure properties.
Strong coordination along the ethoxide group promotes jumps of Li across
positive domains, while in fluorine-poor LILs, stronger coordination in
proximity to boron atoms carries the anion along Li transport. Understanding
the results of MD simulation will aid the further design and widespread use of
this class of electrolytes in production of the energy storage and conversion
devices
