Electrostatic Self-Assembly of Fe3O4 Nanoparticles on Graphene Oxides for High Capacity Lithium-Ion Battery Anodes

Magnetite, Fe 3O 4 , is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g ？1), high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe 3O 4 nanoparticles, composites comprising Fe 3O 4 nanoparticles and graphene sheets (GS) were fabricated. The Fe 3O 4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO) sheets and positively charged Fe 3O 4-APTMS [Fe 3O 4 grafted with (3-aminopropyl)trimethoxysilane (APTMS)] in an acidic solution (pH = 2) followed by in situ chemical reduction. Thus prepared Fe 3O 4/GS composite showed an excellent rate capability as well as much enhanced cycling stability compared with Fe 3O 4 electrode. The superior electrochemical responses of Fe 3O 4/GS composite disks assure the advantages of: (1) electrostatic self-assembly between high storage-capacity materials with GO; and (2) incorporation of GS in the Fe 3O 4/GS composite for high capacity lithium-ion battery application.