Improved storage capacity and rate capability of Fe3O4–graphene anodes for lithium-ion batteries

By employing an ultrasonic deposition followed by heat treatment, magnetite (Fe3O4)–graphene nanosheet (GN) hybrid anode was synthesized to examine its electrochemical performance in Li-ion battery. The Fe3O4 nanocrystals with an average size of 10 nm can be homogeneously incorporated into the GNs to form Fe3O4–GN composites. In comparison with fresh GN anode, the composite anode exhibits high reversible capacity of 753 mAh/g at 0.1 C, high rate capability (533 mAh/g at 5 C), and enhanced cyclic performance with high coulombic efficiency. This improvement can be attributed to the fact that since Fe3O4 acts not only as a redox site but also as a spacer, the Fe3O4–GN hybrid creates a three-dimensional architecture that effectively facilitates ionic diffusion, Li-storage, and electronic transport. This result opens an efficient route for synthesis and application of GN hybrid as anode material for Li-ion batteries with superior performance.