A solvometallurgical approach for the recovery of valuable metals in the recycling of end-of-life batteries

Recycling of critical raw materials from lithium-ion batteries is becoming an unavoidable necessity. Pyro- and hydrometallurgy, which are the processes currently available at industrial level, have relevant issues in terms of sustainability. Solvometallurgy can solve some problems, chiefly about energy and water consumption. Here we report on the use of a ternary deep eutectic solvent (DES) for the microwave-assisted extraction of Lithium, Nickel and Cobalt from a commercial cathode active material (CAM). The optimal composition of the DES and the best experimental parameters are determined by careful experimental design. The most effective DES composition of choline chloride, lactic acid and urea in molar ratio is 1:3:1. The optimal working conditions are 70 °C, an extraction time of 15 min, and a microwave power of 100 W. Under these conditions, the mixture enabled the recovery of more than 95 % of Lithium and over 99 % of Nickel and Cobalt. The extracted metals are subsequently processed to obtain precursors suitable for the synthesis of a new CAM, including 15 % of resynthesized material. The cathode made with a blend of commercial and resynthesized cathode active material gives the same performance of commercial one. • Efficient solvometallurgical method to recover metals from spent Li-ion batteries. • Optimization of DES composition and microwave-assisted process parameters. • Metal recovery from DES via precipitation after the extraction phase. • Resynthesis of cathode materials using metals from DES extraction. • Electrochemical analysis of the resynthesized cathode materials.