Research on the separation process of positive electrode active material and aluminum foil.

• A low-toxicity, efficient, low-cost separation solvent consisting of "propylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][BF 6 ]) ionic liquid" was formulated. • Separation of the positive active material from the aluminium foil up to more than 99%. • The separation solution has little effect on the chemical composition, crystal structure and morphology of the cathode active material, and the surface of the separated aluminium foil is clean and smooth, with little sign of corrosion. • It is universally applicable and can handle any lithium battery electrode using PVDF as the binder, with simple separation equipment, high separation efficiency and easy mass application. Separating the cathode active material and aluminum foil is an important step in the recovery of materials from used lithium-ion batteries. It is difficult to separate aluminum foil and positive active material because of the strong bonding of polyvinylidene fluoride (PVDF). During the conventional stripping technology, using corrosive acids/alkalis, toxic reagents and releasing toxic gases such as dioxins and HF, which are harmful to human health and the environment. In the study, a low-toxic, efficient and low-cost solvent consisting of "propylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][BF 6 ]) ionic liquid" was used to solve these questions. The experimental results showed that the separation rate of the positive active material from the aluminum foil was more than 99 % when the anodes were stirred in propylene glycol and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][BF 6 ]) ionic liquid (the volume ratio of 5:1) at 140 ℃ for 30 min. This work would provide an insight into the environmentally friendly, simple and effective solution to separate of cathode material and aluminum foil in waste lithium-ion batteries. [ABSTRACT FROM AUTHOR]