Low-Carbon and Eco-Friendly Direct Regeneration of Retired LiFePO₄ for Sustainable Lithium-Ion Batteries

Retired LiFePO₄ batteries have posed a significant threat to environmental protection and resource conservation. Efficient, economical and green regeneration of retired LiFePO₄ is crucial to minimizing environmental impact and fostering a true recycling of battery materials. Direct regeneration is an effective strategy, with the principal aspect being the selection of Li⁺ sources and reductants. Here, we report a soft-chemical method to achieve direct regeneration of retired LiFePO₄. One-step lithiation using lithium carbonate and vitamin C is introduced for efficient Li⁺ compensation and structural repair in aqueous solution. Systematic studies reveal phase transformation from FePO₄ to LiFePO₄ during regeneration and demonstrate excellent property recovery accompanied by high structural reversibility of repaired LiFePO₄. Repaired LiFePO₄ from a retired 37 Ah pouch-cell (76.1% capacity retention after 2000 cycles) re-delivers 156.9 mAh g⁻¹ and keeps 81.1% capacity retention after 1000 cycles. 2.1 Ah repaired-LiFePO₄//graphite pouch-cell has 89.5% capacity retention after 500 cycles at 2 C. Furthermore, a comprehensive life-cycle assessment confirms significantly lower energy consumption and environmental footprint through life-cycle compared with Pyro- and Hydro-recycling methods. This method utilizes readily available, low-cost and environmental-friendly reagents, offering substantial advantages over traditional techniques, representing an efficient and economical route for sustainable recycling of retired Li-ion batteries.