Upcycling Spent Graphite into Fluorine-Doped Reduced Graphene Oxide Anodes for High-Performance Lithium-Ion Batteries
摘要
Fluorine-doped reduced graphene oxide (FRGO) was synthesized from spent graphite (SG) by first producing reduced graphene oxide (RGO) via potassium permanganate-assisted oxidation and thermal reduction, followed by fluorination with lithium hexafluorophosphate. The optimized material, FRGO-3, exhibited an expanded interlayer spacing of 0.375 nm, an ultrahigh specific surface area of 1 433.86 m2·g−1, and a high fluorine doping content of 3.6%. Fluorine incorporation was predominantly achieved in semi-ionic and co-valent C-F configurations. Owing to these structural and chemical characteristics, FRGO-3 demonstrated remarkable lithium storage performance, including a high reversible capacity of 1 323 mAh·g−1 at 50 mA·g−1 and a retained capacity of 489 and 318 mAh·g−1 even at a high current density of 1 000 and 2 000 mA·g−1, along with excellent cycling stability. These results underscore its potential as an advanced anode material for high-performance lithium-ion batteries(LIBs). This work presents an efficient and scalable approach for the regeneration of waste graphite while unlocking its promise for sustainable LIB applications.