Characterization of thermal mass transfer in the separation process of electrode materials from spent lithium-ion batteries using deep eutectic solvents

Abstract

With the transformation of the global energy structure, the lithium-ion battery (LIBs) market continues to expand, resulting in the number of spent LIBs increasing year by year. Spent LIBs contain valuable metals such as lithium, cobalt, and nickel, which can lead to severe environmental pollution and loss of critical resources without proper managements. The separation of cathode active materials from the current collector is crucial for enhancing metal recovery from spent LIBs. Conventional organic solvents have demonstrated effective separation performance; however, their high toxicity and volatility pose significant safety concerns, limiting the practicality of these methods in the recovery process. In this study, the use of novel green solvent, deep eutectic solvent (DES), was explored as the separation medium. The effects of various factors, including component structure, group distribution ratio, reaction temperature, and the application of external ultrasound, on the peel efficiency of cathode materials from spent LIBs were investigated. In this study, a 100% peel efficiency was achieved when aluminum foil reacted with cathode active material in a KAc-EG (1:3) DES at 160°C for 30 minutes. This work provides significant reference value for the mild and environmentally friendly separation of cathode materials from spent LIBs.