Facile Synthesis of Hollow Mesoporous CoFe2O4 Nanospheres and Graphene Composites as High-Performance Anode Materials for Lithium-Ion Batteries

A novel, facile, self-assembly approach, based on a gas-bubble-template model and assisted by graphene oxide, is developed to fabricate hollow 3D mesoporous CoFe2O4 nanospheres (NSs) and graphene composites. During the hydrothermal process, the oxygen-containing functional groups and defect sites on the graphene sheets act as nucleation centers to anchor released gas bubbles, providing a soft template for the aggregation of nanosized CoFe2O4 crystallite building blocks to form NSs. Benefiting from the synergistic effect between the hollow 3D mesoporous CoFe2O4 NSs and graphene, the electrode exhibited remarkable electrochemical performance with a high reversible capacity (approximate to 1030 mAhg(-1) after 60cycles at 100 mAg(-1)), enhanced rate capability (approximate to 970, approximate to 850, approximate to 555 mAhg(-1) at 100, 500, 5000 mAg(-1), respectively), and superior cyclic stability (approximate to 805 mAhg(-1) after 305cycles at 2000 mAg(-1) with a high coulombic efficiency of approximate to 99.5%); these composites are thus high-performance anode materials for lithium ion batteries.