In situ preparation of Fe 3 O 4 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 Fe ₃ O ₄ nanoparticles through an in situ synthesis method. As an anode material for LIBs, the obtained Fe ₃ O ₄ @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 Fe ₃ O ₄ and Fe ₃ O ₄ /rGO composite anode materials without nanoscroll structure, Fe ₃ O ₄ @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 Fe ₃ O ₄ @rGNSs-CNTs anode material can be ascribed to the hybrid structure of rGNSs-CNTs, and their strong interaction with Fe ₃ O ₄ nanoparticles, which on one hand provides more pathways for lithium ions and electrons, on the other hand effectively relieves the volume change of Fe ₃ O ₄ during the charge-discharge process.