AbstractThe solvent extraction of Li+ by Cyanex 923 was investigated upon the addition of different imidazolium‐based ionic liquids (ILs). The results showed 1‐hydroxylethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf2]) can improve the extraction of Li+ most effectively. The fundamental mechanism is that [HOEmim][NTf2] can remarkably enhance the coordination ability of Cyanex 923 to Li+ to form more stable and hydrophobic ion‐pair species [Li(Cyanex 923)n][NTf2] (nmax = 3) resulting from the electrostatic interaction and typical hydrogen bonding of IL, and thus facilitating the transfer of Li+ into organic phase. This work has revealed the transfer mechanism of Li+ in a solvent extraction system comprising of IL and neural ligand. The knowledge of the coordination environment of Li+ in the presence of IL also gives us a new insight into the separation of 6Li/7Li. The disadvantage of this process is the loss of IL. However, this study provides guidance for the design of better IL‐based systems for the separation of metal ions.