Selective separation of cathode materials from aluminum foils using bio-based ethyl lactate: Mechanism and application to direct LiFePO4 regeneration

Ethyl lactate (EL) enables green delamination of spent LFP cathodes via a closed-loop recycling strategy. • Competitive H-bonding selectively breaks PVDF-Al interface, achieving >98% separation efficiency. • Regenerated LFP delivers 144.0 mAh g −1 and 97.8% retention after 300 cycles, matching benchmarks. • EL process cuts energy use by 67% versus NMP, offering high economic returns with zero toxicity. Recycling spent lithium ion phosphate (LFP) batteries faces significant challenges due to the strong adhesion between the cathode active material (CAM) and aluminum (Al) current collector, often requiring corrosive chemicals or toxic solvents that compromise material integrity and generate hazardous waste. Herein, we report a sustainable delamination strategy utilizing bio-based ethyl lactate (EL), a green solvent, to achieve efficient and selective separation under mild thermal conditions (85 °C). Unlike conventional methods, EL disrupts the interfacial bonding via competitive hydrogen bonding, selectively targeting the polyvinylidene fluoride (PVDF) binder without corroding the Al substrate, thereby enabling the high-purity recovery of both components. The resulting delaminated LFP, free from organic impurities undergoes a streamlined direct regeneration via hydrothermal relithiation and calcination to restore its stoichiometry and crystallinity. The regenerated LFP delivers a high initial discharge capacity of 144.0 mAh g −1 with 97.8% capacity retention after 300 cycles at 1C, outperforming materials from conventional recycling routes. Techno-economic and life-cycle assessments reveal that the EL process operates with 67% lower energy intensity than the NMP benchmark, avoids toxic solvent degradation, and achieves superior economic returns by minimizing reagent consumption and maximizing the recovery of high-value materials. This work establishes a closed-loop, green, and industrially viable pathway for sustainable LPF battery recycling. Ethyl lactate (EL) selectively dissolves the binder and weakens interfacial adhesion, enabling gentle delamination of active material from aluminum foil. The recovered material is directly regenerated into high-performance cathode powders, which are then reassembled into new lithium-ion batteries, closing the loop in sustainable battery recycling. Download: Download high-res image (216KB) Download: Download full-size image