Encapsulation of Fe₃O₄ Nanoparticles into N, S co-Doped Graphene Sheets with Greatly Enhanced Electrochemical Performance

Particular N, S co-doped graphene/Fe₃O₄ hybrids have been successfully synthesized by the combination of a simple hydrothermal process and a subsequent carbonization heat treatment. The nanostructures exhibit a unique composite architecture, with uniformly dispersed Fe₃O₄ nanoparticles and N, S co-doped graphene encapsulant. The particular porous characteristics with many meso/micro holes/pores, the highly conductive N, S co-doped graphene, as well as the encapsulating N, S co-doped graphene with the high-level nitrogen and sulfur doping, lead to excellent electrochemical performance of the electrode. The N-S-G/Fe₃O₄ composite electrode exhibits a high initial reversible capacity of 1362.2 mAh^-1, a high reversible specific capacity of 1055.20 mAh^-1 after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 556.69 mAh^-1 when cycled at the current density of 1000 mA^-1, indicating that the N-S-G/Fe₃O₄ composite is a promising anode candidate for Li-ion batteries.