MOF-Derived Octahedral-Shaped Fe3O4@C Composites for Lithium Storage

Despite the high theoretical capacity of iron-based anode materials, they still perform poorly in electrical conductivity and volume expansion during the charge/discharge process, which can reduce battery life and cause deterioration in cycle performance. In the present study, iron-based metal–organic frameworks are synthesized through a simple co-precipitation method, and then heat-treated as a self-sacrificing template to obtain carbon-coated Fe 3 O 4 of a porous ortho-octahedral structure. As revealed by electrochemical performance studies, this material maintains a high specific capacity, showing a reversible capacity of 1063 mAh/g and 896 mAh/g after 300 cycles at a current density of 0.5 A/g and 1 A/g. By analyzing the functional mechanism of surface carbon coating, it is demonstrated that the fast ion migration and high electrical conductivity required for fast charging and discharging are ensured by the octahedral and hierarchical void structure of the carbon framework. This study thus provides a reference for the design of high-performance electrode materials. Graphical Abstract