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

Magnetite, Fe3O4, 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 Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS) were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO) sheets and positively charged Fe3O4-APTMS [Fe3O4 grafted with (3-aminopropyl)trimethoxysilane (APTMS)] in an acidic solution (pH = 2) followed by in situ chemical reduction. Thus prepared Fe3O4/GS composite showed an excellent rate capability as well as much enhanced cycling stability compared with Fe3O4 electrode. The superior electrochemical responses of Fe3O4/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 Fe3O4/GS composite for high capacity lithium-ion battery application.