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][BF6]) 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.