Selective separation of critical metals from lithium-ion batteries in a two-phase leaching system based on a hydrophobic deep eutectic solvent and H 2 O 2 solution

A two-phase system using a hydrophobic deep eutectic solvent (2 mol of 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione: 1 mol tri- n -octylphosphine oxide) and H 2 O 2 enabled selective recovery of Li, Co, Ni, and Mn from spent lithium-ion batteries.