Synthesis of 3D Hierarchical Fe3O4/Graphene Composites with High Lithium Storage Capacity and for Controlled Drug Delivery

Three-dimensional (3D) hierarchical Fe3O4/graphene nanosheet (GNS) composites have been synthesized using a simple in situ hydrothermal method. Characterization shows that the Fe3O4 nanoflowers are highly encapsulated in a GNS,matrix. The Fe3O4/GNSs-1 nanocomposite (60 wt % of Fe3O4 in the composites) exhibits a stable capacity of similar to 605 mAh g(-1) with no noticeable fading for up to 50 cycles in the voltage range of 0.001-3.0 V, and the superior performance of Fe3O4/GNSs-1 is clearly established by comparison of the results with those from Fe3O4/GNSs-2 (23 wt % of Fe3O4 in the composites) and bare Fe3O4. In addition, another possible application of the drug delivery with the composites shows that the loading of rhodamine B (RB) on Fe3O4/GNSs increased linearly with the increase in the initial RB concentration, and the loading capacity of Fe3O4/GNSs-1 was as high as 3.18 mg mg(-1). The excellent electrochemical performance of the :Composites and highly efficient loading of RB Could be attributed to the enhanced electronic conductivity and the large. surface areas of the Fe3O4/GNSs in which the hierarchical structure of Fe3O4 nanoflowers are highly encapsulated in the GNS matrix.