Synthesis of well-defined Fe3O4 nanorods/N-doped graphene for lithium-ion batteries

Electrostatic assembly between Fe3O4 nanospheres and graphene oxide, and subsequent hydrothermal assembly with additional graphene sheets, leads to Fe3O4 nanospheres encapsulated in the graphene shells and interconnected by the graphene networks. Such 3D Fe3O4 /graphene foams exhibit enhanced lithium storage with excellent cycling performance and rate capability.

Fe3O4 has long been regarded as a promising anode material for lithium ion battery due to its high theoretical capacity, earth abundance, low cost, and nontoxic properties. However, up to now no effective and scalable method has been realized to overcome the bottleneck of poor cyclability and low rate capability. In this article, we report a bottom-up strategy assisted by atomic layer deposition to graft bicontinuous mesoporous nanostructure Fe3O4 onto three-dimensional graphene foams and directly use the composite as the lithium ion battery anode. This electrode exhibits high reversible capacity and fast charging and discharging capability. A high capacity of 785 mAh/g is achieved at 1C rate and is maintained without decay up to 500 cycles. Moreover, the rate of up to 60C is also demonstrated, rendering a fast discharge potential. To our knowledge, this is the best reported rate performance for Fe3O4 in lithium ion battery to date.