In situ preparation of Fe₃O₄ in a carbon hybrid of graphene nanoscrolls and carbon nanotubes as high performance anode material for lithium-ion batteries

A new conductive carbon hybrid combining both reduced graphene nanoscrolls and carbon nanotubes (rGNSs-CNTs) is prepared, and used to host Fe₃O₄ nanoparticles through an in situ synthesis method. As an anode material for LIBs, the obtained Fe₃O₄@rGNSs-CNTs shows good electrochemical performance. At a current density of 0.1 A g⁻¹, the anode material shows a high reversible capacity of 1232.9 mAh g⁻¹ after 100 cycles. Even at a current density of 1 A g⁻¹, it still achieves a high reversible capacity of 812.3 mAh g⁻¹ after 200 cycles. Comparing with bare Fe₃O₄ and Fe₃O₄/rGO composite anode materials without nanoscroll structure, Fe₃O₄@rGNSs-CNTs shows much better rate capability with a reversible capacity of 605.0 and 500.0 mAh g⁻¹ at 3 and 5 A g⁻¹, respectively. The excellent electrochemical performance of the Fe₃O₄@rGNSs-CNTs anode material can be ascribed to the hybrid structure of rGNSs-CNTs, and their strong interaction with Fe₃O₄ nanoparticles, which on one hand provides more pathways for lithium ions and electrons, on the other hand effectively relieves the volume change of Fe₃O₄ during the charge–discharge process. (paper)