Effective separation of cathode active materials from Al foil is a critical step in the recycling of spent lithium-ion batteries (LIBs). Conventional techniques, including thermal treatment, organic solvent dissolution, and alkaline etching, are often associated with challenges such as incomplete separation, high energy demand, and environmental hazards. In this study, a green organophosphonic acid, 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP), was utilized to achieve rapid and effective delamination of LiNi