Efficient regeneration and reutilization of degraded graphite as advanced anode for lithium-ion batteries

Highlights: • This approach achieves efficient and rapid separation of copper foil and waste graphite. • The (NH₄)₂S₂O₈ plays an important of in purification and structural repairation of waste graphite. • The regenerated graphite exhibits excellent Li-storage performance. • This approach provides potential application prospects in the industry. -- Abstract: As a burgeoning solid waste, it is of great significance for spent lithium-ion batteries (LIBs) that recovering graphite anode and valuable lithium simultaneously to achieve resource utilization and environmental protection. However, two major troubles, difficult separation and degraded structure, have stagnated the recycling of spent graphite anode. Hence, we propose an approach to achieve the separation of collector/graphite and structural restoration of graphite anode synchronously. Benefited from the acidity and oxidability of ammonium persulfate, the recovered graphite with enlarged layer spacing is successfully obtained. When assembled in coin-cell, it exhibits excellent lithium storage performance with high reversible capacity (365.3 mAh g⁻¹ after 100 cycles at 0.03 A g⁻¹) and long cyclic life (330.2 mAh g⁻¹ after 500 cycles at 0.3 A g⁻¹), which is apparently higher than that of spent graphite and closed to that of commercial graphite. Furthermore, renewed graphite anode also demonstrates negligible difference with commercial graphite in electrochemical performance for full-cells, manifesting the sustainable meritoriousness of this recycling process. This recycling approach with the advantages of green, efficiency, and conciseness has the application prospects for industrial recycling of graphite anode of spent LIBs.