Efficient utilization of scrapped LiFePO4 battery for novel synthesis of Fe2P2O7/C as candidate anode materials

Abstract With the increasing retirement of LiFePO4 batteries, state-of-the-art recycling strategies have drawn widespread attention for sustainable resource development. However, critical issues, such as tedious procedures and improper disposal of hazardous wastes, need to be solved urgently and efficiently. Generally, the recovery of lithium is emphasized during the recycling process, yet the relatively low valuable Fe/P compounds are rarely concerned, which are considered as hazardous materials. Herein, a simplified and economical method is developed to treat spent lithium-ion batteries (LIBs) by utilizing LiFePO4 cathode scraps as the raw precursors to fabricate novel anode material Fe2P2O7. Specifically, thermodynamic analysis confirms the feasibility of the selective extraction of lithium and synchronous separation of Li/Fe/Al elements. Under the optimal experimental parameters, the leaching efficiency of lithium can reach up to 98.84% and that of Fe/Al is below 1%, demonstrating the superior selectivity of lithium. Significantly, the waste leaching slag FePO4 is flexibly utilized to regenerate Fe2P2O7, which is applied as a novel anode material for LIBs and exhibits satisfactory rate capability and competitive long-term cycling stability (reversible capacities of 147.2 mAh g−1 at 1.0 A g−1 after 500 cycles with an excellent retention of 88.55%). This presented strategy takes full advantages of spent batteries by recycling the valuable fragments and turning solid waste into value-added anode materials simultaneously. It is convinced that the potential “waste to treasure” approach provides an environmental-friendly technology to reutilize the spent LIBs, which achieves the interdisciplinary of resource recycling and energy storage area.