Green & efficient regeneration of graphite anode from spent lithium ion batteries enabled by asphalt coating

The recycling of spent graphite anode is often discarded due to its low added value and strict separation procedures. However, if the graphite (about 10%) contained in spent lithium-ion batteries (LIBs) is not properly treated, it will cause waste of resources and environmental pollution. In addition, the spent graphite still has great potential to be reused as anode material for LIBs. In this paper, we report a direct regeneration process for spent graphite anode. Using asphalt as the coated carbon source and spent graphite as the core, the asphalt pyrolyzed carbon@graphite composites were obtained by a liquid phase impregnation method and high temperature treatment. Benefiting from the high temperature repair, the structure of spent graphite was reconstructed, which led to an increase in the interlayer lattice distance and the degree of graphitization. The modification with asphalt coating reduces the aggregation of spent graphite particles and results in a smoother surface morphology. When used as anode materials for LIBs, the regenerated graphite exhibits satisfactory electrochemical performance. Accordingly, it can deliver a high initial specific capacity of 403 mAh g−1 at 0.1C, which is larger than that of graphite (372 mAh g−1). It also exhibits excellent initial coulombic efficiency (ICE) (95.5%) and a high reversible capacity of 394 mAh g−1 at 0.1C over 110 cycles (high capacity retention of 97.8%). The results indicate that the effective regeneration of graphite anode from spent lithium-ion batteries (S-LIBs) has enormous potential in the application of batteries.