Fenton-induced Self-catalyzed Exfoliation-Leaching Coupling Reactions towards Short-cut and Closed-loop Recycling of Spent Lithium-ion Batteries.

The rapid growth of retired lithium-ion batteries (LIBs) from new energy vehicles and energy storage systems has posed a severe challenge for the disposal of spent batteries. Conventional recycling technologies generally require large amounts of chemicals and energy input, accompanied with potential secondary environmental contaminations. Herein, an environmentally benign recycling strategy based on Fenton advanced oxidation process (FAOP) was proposed to liberate cathode materials of lithium iron phosphate (LiFePO4, LFP) from current collectors (Al foils) and extract Li from liberated the LFP, followed by a closed-loop regeneration of cathode materials was achieved using recovered resources (Li3PO4 and FePO4). Specifically, Fe(II) in waste LFP can activate H2O2 to generate active oxide species of 1O2 and free radicals (•OH or •O2-), enabling simultaneous degradation of polyvinylidene fluoride (PVDF) binders and selective leaching of Li, which lead to the effective separation of LFP from Al foils and selective extraction of Li. Under optimized conditions, the cathode material peeling efficiency and lithium leaching efficiency reached 98.99% and 96.78%, respectively. Then, the leaching residues can be separated as Al foil sheets and FePO4 powders, while Li+ in the leaching solution was precipitated as Li3PO4. The regenerated LFP synthesized using recycled Li3PO4 and FePO4 exhibits comparable electrochemical performances to commercial cathode materials. This developed strategy provides an efficient and green route for the closed-loop recycling of spent LIBs with low chemical consumption.