Graphene anchored with Fe3O4 nanoparticles as anode for enhanced Li-ion storage

Abstract

Magnetite (Fe3O4) nanoparticles anchored graphene nanocomposites with different weight ratios of Fe3O4 and graphene nanosheets (GNSs) were prepared using hydrothermal method. The X-ray diffraction (XRD) pattern of the prepared nanocomposite reveals the presence of face centered cubic hexagonal crystalline Fe3O4 nanoparticles. Raman spectroscopic studies of the nanocomposites confirm the co-existence of Fe3O4 and graphene. The electron microscopy images of the nanocomposites revealed the formation of homogeneous nanocrystalline Fe3O4 particles on GNS surface. Among the three studied weight ratios (28:72, 40:60 and 60:40), the charge–discharge profile of the nanocomposite electrodes indicates that nanocomposite with 40:60 wt% of Fe3O4 and GNS as high capacity (930 mAh g−1) electrode for the lithium-ion (Li-ion) storage. And, the Li-ion storage capacity of the above nanocomposite is much higher than the pure GNS and Fe3O4 nanoparticle electrodes. The charge–discharge cycling study indicates that the Fe3O4/GNS (40:60) nanocomposite electrode has very high reversible capacity of 675 mAh g−1 with columbic efficiency of 97% after 50 cycles. The rate performance of the Fe3O4/GNS (40:60) nanocomposite electrode shows high reversible capacities at high rates due to the high conductive GNS support. The cyclic voltammetry experiment reveals the irreversible and reversible Li-ion storage in Fe3O4/GNS during the first and subsequent cycles.