Hierarchical Fe3O4@C nanospheres derived from Fe2O3/MIL-100(Fe) with superior high-rate lithium storage performance

Abstract Carbon coating is one of the most effective strategies to improve the electrochemical performance of nanostructured transition metal oxides (TMOs). Herein, we report a facile and scalable method to prepare hierarchical Fe 3 O 4 @C nanospheres. The fabrication includes one-step solvothermal synthesis of Fe 2 O 3 /MIL-100(Fe) precursor and subsequent annealing treatment in Ar. The Fe 3 O 4 @C nanospheres with an average size of about 200 nm are composed of many interconnected small nanoparticles, with an amorphous carbon layer on the surface of Fe 3 O 4 , exhibiting a unique hierarchical nanostructure with a larger specific surface area of 176.5 m 2  g −1 . The hierarchical Fe 3 O 4 @C nanosphere electrode delivers a high capacity of 757.9 mAh g −1 after 500 cycles at a current density of 500 mA g −1 , demonstrating superior high-rate lithium storage performance. This may be ascribed to the unique hierarchical nanoarchitecture, higher specific surface area and the uniform carbon layer in-situ generated from MIL-100(Fe).