the viscosity of various ionic liquids , the solvent tetraethylene glycol dimethyl ether , and their mixtures , with or without lithium salts , were measured experimentally . various compositions were studied spectroscopically . detailed analysis reveals that g4 preferentially solvates cations , leading to a reduction in the interaction energy between cations and anions and a subsequent enhancement in anion mobility . diffusivity and ionic conductivity of certain compositions were improved at g4 mole fractions below levels required for a “ solvate ionic liquid ”. when an il was combined with low amounts of a 1 : 1 stoichiometric ratio of g4 and lithium salt , the viscosity of composition remained constant and ion mobility increased .