The overlooked front-end step in high-quality LiFePO₄ cathode recycling: staged thermal pretreatment and water-flushing delamination for cathode active material harvesting

High-quality recovery of cathode active materials from spent lithium-ion batteries requires effective front-end delamination of electrode sheets; however, this critical step is often overlooked and remains limited by mechanical damage, solvent consumption, and uncontrolled thermal degradation. Here, we develop a staged thermal pretreatment–water-flushing delamination strategy for low-damage harvesting of LiFePO₄ (LFP) cathode active materials. Mechanistic investigations reveal that thermal activation induces PVDF chain scission, reducing binder cohesion and facilitating interfacial decoupling between the active coating and the Al current collector, while controlled water flushing provides directional hydraulic shear to achieve selective coating separation without severe particle fragmentation or Al contamination. Multiphysics simulation further demonstrates that thermal pretreatment reduces interfacial stress concentration and lowers the mechanical resistance required for delamination. An integrated delamination system was established to validate the scalability of the proposed approach for practical spent cathode laminates. The harvested LFP materials retain the original olivine framework, particle morphology, and reversible electrochemical activity, while surface contaminants are effectively reduced. Techno-economic analysis highlights the potential advantages of this process over conventional mechanical crushing and solvent-based recycling routes. This work emphasizes electrode-sheet delamination as a decisive front-end step and provides a practical pathway toward high-quality black-mass recovery and short-loop regeneration of spent lithium-ion batteries.