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. (C) 2011 Elsevier Ltd. All rights reserved.