Natural Low-Melting Mixture Solvents for Green Recovery of Spent All-Solid-State Sodium-Ion Batteries with Superior Efficiency over Lithium-Ion Batteries

Graphical Natural low-melting mixture solvents could be used to achieve mild, safe and efficient recovery of all-solid-state electrolyte and cathode from all-solid-state sodium-ion batteries with high selectivity. Moreover, water is found to be the green and low-cost anti-solvent to precipitate the extracted metal from the leachate with low-energy consumption at room temperature. Spent all-solid-state sodium-ion batteries (ASIBs) containing toxic and precious metal would be produced significantly and lead to resource waste and environmental pollution as the wide application of ASIBs in the near future. Therefore, it is necessary to develop green strategy for recovery of ASIBs. Here, we propose a safe, mild and green strategy to recover toxic and precious metals from cathode/solid electrolyte of ASIBs by using natural low-melting mixture solvents (LoMMSs) with high selectivity and high leaching efficiency. Natural LoMMSs are abundant, natural available, cheap, non-flammable, biodegradable and biocompatible. Results show that natural LoMMSs could leach nearly 100 % Na and achieve superhigh Na/Zr selectivity of up to 58 from ASIBs at mild temperature, outperforming the recycling efficiency and selectivity of lithium-ion batteries cathode. More importantly, we find that water could be used as a green and low-cost anti-solvent to precipitate the extracted metal from the leachate with low-energy consumption at room temperature. This work provides a cost-effective, energy-saving, mild, green strategy for the recovery of cathode/solid electrolyte from spent ASIBs with high safety and high selectivity.