Enhancing lithium extraction with π‐electron donor‐based ionic liquids: Molecular thermodynamics and dynamic insights

This study proposes a novel strategy for enhancing Li + extraction from brines by π‐electron donor‐based ionic liquid (IL) extractant systems. The binary extractant system of [A 2 MIM][Tf 2 N] and tri‐isobutyl phosphate was experimentally selected, with a single‐stage extraction efficiency of up to 95.87% and separation selectivity of Li + /Mg 2+ of 817.15, respectively. The molecular‐level mechanism for Li + extraction was unraveled by quantum chemical calculations and molecular dynamics simulations. It is found that enhancing Li + extraction with the π‐electron donor‐based IL serves two main aspects of increasing the hydrogen bond interaction of the IL–cation and H 2 O resulting in Li + hydration (Li + ···O‐H) disruption and improve Li + transfer into the organic phase by more competitive coordination of Li + ‐[Tf 2 N] − (Li + ···O=S), namely, the so‐called “Li + hydration disruption‐phase transfer enhancement induced by π‐electron donor‐based ILs” effect. This work provides a theoretical guidance for developing high‐efficiency IL‐based extractants for Li + extraction.