Elucidation of cube-like red iron oxide @ carbon nanofiber composite as an anode material for high performance lithium‐ion storage

• A facile hydrothermal technique is used to prepare nano-cube-type RIO@CF composite followed by calcination process and used as an anode for LIBs. • As-prepared nano-cube-type RIO@CF composite shows the higher surface area than the pristine RIO. • Nano-cube-type RIO@CF composite shows the highest capacity of 1138 mAh g −1 after 150 cycles at a current density of 100 mA g −1 . • Nano-cube-type RIO@CF composite delivers better cyclic performance as compared to the pristine RIO. Herein, a red iron oxide @ carbon fiber (RIO@CF) composite is prepared via a simple and effective single hydrothermal and calcination process. The physico-chemical characteristics of as-prepared electrode active materials are examined by X-ray photoelectron spectroscopy, high resolution field emission-scanning electron microscopy and field emission-tunneling electron microscopy analyses. When used as the anode material in the Li-ion battery, as-prepared RIO@CF composite have shown a specific capacity of 1138 mAh g −1 after 150 cycles with a capacity retention of 86% at a current density of 100 mA g −1 . Moreover, a specific capacity of 825 mAh g −1 is achieved in the first cycle at a current density of about 5000 mA g −1 . Thus, when compared to the pristine nano-cube-like red iron oxide (RIO) electrode material, the RIO@CF composite electrode exhibits an outstanding cyclic stability and rate capacity. This electrochemical enhancement facilitates effective lithium ion transport into the RIO@CF composite electrode, thus improving the electrical conductivity. In addition, the application of a homogeneous carbon fiber coating can provide effective contact between the electrode surface and the electrolyte to further benefit the electrochemical performance.