Reviving Lithium: A Sustainable Approach to Recover Lithium Metal from Spent Lithium-Ion Batteries Using Deep Eutectic Solvents

Leaching of lithium-ion batteries (LIB) is the main step for recovery of lithium from spent batteries. In the present study, choline chloride (ChCl) and synthesized cattle urea were used to dissolve lithium with 92.2 % leaching efficiency at 80 °C for 72 h. Cattle urea was synthesized by collecting fresh cattle urine, filtering it to remove impurities, and evaporating the filtrate at 120 °C until crystalline urea was obtained. As per our knowledge, this is the first study to report the application of urea synthesized from cattle urine in DESs. The presence of the characteristic FTIR peaks revealed the structural information of urea and DES. The density and the viscosity of the DES sample was determined to be 1.20 g/cc and 13.2 cP respectively. Efficient leaching was seen using 10 mL DES for 5 g of the mixture at 80 °C for 72 h and ICP-MS showed efficient lithium recovery. Mica efficiently adsorbed lithium ions from solution through ion exchange and surface complexation due to its layered structure and large surface area. Desorption was achieved by solvent washing or thermal treatment to release adsorbed species. This study could pave the way for further exploration into the extraction of lithium from disposed batteries.