Selective and Sustainable Recovery of Lithium and Cobalt from Spent Batteries Using Green Solvents: A Comprehensive Experiment for Undergraduates

The escalating global demand for lithium-ion batteries (LIBs) has intensified the urgency for recycling strategies, presenting an environmental challenge and an opportunity to integrate cutting-edge sustainable research into undergraduate education. This comprehensive laboratory experiment for undergraduate students focuses on the selective and sustainable recovery of lithium (Li) and cobalt (Co) from spent LiCoO 2 (LCO) cathodes using a deep eutectic solvent (DES) system. Students engage in a four-step procedure involving DES synthesis, LCO leaching, stepwise Li/Co separation accompanied by coordination-driven color changes, and product characterization. The experiment leverages intuitive visual cues, namely, the transition from the deep blue [CoCl 4 ] 2– to the pink [Co(H 2 O) 6 ] 2+ species, illustrating fundamental concepts in green chemistry, coordination chemistry, and separation engineering. Students could also gain experience in interpreting data from modern analytical techniques, including ICP-OES, XRD, FT-IR, and SEM. The experiment can be adapted for lower-division students focusing on conceptual understanding and hands-on experience or upper-division students exploring mechanism insights and DES regeneration possibility. Assessment results indicate that the experiment improves students’ comprehension of green chemistry and coordination chemistry as well as their inspiration for pursuing careers in the circular economy. This experiment offers a simple, green, and visually engaging platform for fostering interdisciplinary problem-solving and advancing the principles of the circular economy in the undergraduate laboratory.