Organic phosphorus‐based ionic liquids for extraction of valuable metals from spent lithium‐ion batteries

Abstract Traditional phosphonic acid extractants such as P507 often exhibit limited extraction efficiency. Herein, a synergistic extraction strategy is developed to enhance the recovery and separation of valuable metals from acidic leachates of spent lithium‐ion batteries (LIBs) by modulating P507 with lidocaine (Lid), thereby eliminating the need for saponification pretreatment and acidification. Metal extraction proceeds via combined cation‐exchange and coordination mechanisms. Quantum chemical calculations and molecular dynamics simulations reveal the metal‐binding sites in the ionic liquid [LidH][P507], providing theoretical guidance for synergistic extractant design. The system achieves high recoveries of Co 2+ (98.85%), Ni 2+ (95.13%), and Mn 2+ (99.97%), with separation factors of up to 250.56 (), 56.70 (), and 10623.11 (). Efficient and selective Li + recovery is also demonstrated. This work provides guidance for the rational design of IL‐based extractants and offers an efficient, solvent‐free strategy for spent LIB recycling.