Abstract
The ubiquitous manufacturing of lithium-ion batteries(LIBs) dueto high consumer demand produces inevitable e-waste that imposes severeenvironmental and resource sustainability challenges. In this work,the charge storage capability and Li-ion kinetics of the recoveredwater-leached graphite (WG) anode from spent LIBs are enhanced byusing an optimized amount of recycled graphene nanoflakes (GNFs) asan additive. The WG@GNF anode exhibits an initial discharge capacityof 400 mAh g(-1) at 0.5C with 88.5% capacity retentionover 300 cycles. Besides, it delivers an average discharge capacityof 320 mAh g(-1) at 500 mA g(-1) over 1000cycles, which is 1.5-2 times higher than that of WG. The sharpincrease in electrochemical performance is due to the synergisticeffects of Li-ion intercalation into the graphite layers and Li-ionadsorption into the surface functionalities of GNF. Density functionaltheory calculations reveal the role of functionalization behind thesuperior voltage profile of WG@GNF. Besides, the unique morphologyof spherical graphite particles trapping into graphene nanoflakesprovides mechanical stability over long-term cycling. This work explainsan efficient strategy to upgrade the electrochemical compatibilityof recovered graphite anode from spent LIBs toward next-generationhigh-energy-density LIBs.