New functionalized ionic liquids based on multi-methoxyethyl substituted quaternary ammonium cations and perfluorinated sulfonimide anions are introduced. New functionalized ionic liquids (ILs), comprised of multi-methoxyethyl substituted quaternary ammonium cations (i.e. N(CH 2CH 2OCH 3) 4− n (R) n +; n = 1, R = CH 3OCH 2CH 2; n = 1, R = CH 3, CH 2CH 3; n = 2, R = CH 3CH 2), and two representative perfluorinated sulfonimide anions (i.e. bis(fluorosulfonyl)imide (FSI −) and bis(trifluoromethanesulfonyl)imide (TFSI −)), were prepared. Their fundamental properties, including phase transition, thermal stability, viscosity, density, specific conductivity and electrochemical window, were extensively characterized. These multi-ether functionalized ionic liquids exhibit good capability of dissolving lithium salts. Their binary electrolytes containing high concentration of the corresponding lithium salt (Li + >1.6 mol kg −1) show Li + ion transference number ( t L i + ) as high as 0.6–0.7. Their electrochemical stability allows Li deposition/stripping realized at room temperature. The desired properties of these multi-ether functionalized ionic liquids make them potential electrolytes for Li (or Li-ion) batteries.