Synthesis of iron oxide cubes/reduced graphene oxide composite and its enhanced lithium storage performance

A Fe3O4/rGO composite with monodispersed Fe3O4 submicron cubes enwrapped by the rGO sheets is prepared by a facile hydrothermal reaction followed with high temperature treatment. This composite exhibits superior Li-storage performance to its parent Fe3O4 submicron cubes, especially the long-term cycling stability. [Display omitted] Fe3O4 is considered as a promising electrode material for lithium-ion batteries (LIBs) due to its low cost and high theoretical capacity (928 mAh/g). Nevertheless, the huge volume expansion and poor conductivity seriously hamper its practical applications. In this study, we use a facile hydrothermal reaction together with a post heat treatment to construct the three-dimensional heterostructured composite (Fe3O4/rGO) inwhich reduced graphene oxide sheets wraped the Fe3O4 submicron cubes as the conductive network. The electric conduction and electrode kinetics of lithium ion insertion/extraction reaction of the composite is enhanced due to the assist of conductive rGO, and thus the Li-storage performance is obviously improved. The composite exhibits a reversible charge capacity of 772.1 mAh/g at the current density of 0.1 A/g, and the capacity retention reaches 70.3% after 400 cycles at 0.5 A/g, demonstrating obviously higher specific capacity and rate capability over the Fe3O4 submicron cubes without rGO, and much superior cycling stability to the parent Fe2O3 submicron cubes without rGO. On the other hand, as a synergic conductive carbon support, the flexible rGO plays an important role in buffering the large volume change during the repeated discharge/charge cycling.