Direct Recycling of Ternary Lithium-Ion Batteries via Solvent-Assisted Separation of Cathode Materials

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_0.55Co_0.15Mn_0.3O₂ cathode materials from Al foil. Complete separation was accomplished in just 4 min under mild conditions, with Al leaching as low as 4.58%. Mechanistic investigations revealed that HEDP reacts with Al foil to form a compact passivation layer on its surface, effectively suppressing further corrosion and reducing binder adhesion. This eco-friendly and cost-effective approach offers a sustainable solution for the recycling of spent LIBs.