Fe3O4C open hollow sphere assembled by nanocrystals and its application in lithium ion battery

This article reports a solvothermal method to fabricate sub-micrometer hematite α-Fe2O3 hollow sphere, and Fe3O4C sphere is obtained with further carbothermal reduction process. The key trick of the solvothermal method is to use crystal water of the raw material Fe(NO3)3·9H2O as the water phase in the water/oil “micro-reactor” system. Interestingly, one hole is found on the surface of almost each α-Fe2O3/Fe3O4 hollow sphere. The obtained material is characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmer–Teller analysis, elemental analysis and its electrochemical properties are also studied. This Fe3O4C composite material shows a high reversible capacity of 917.3 mAh g−1 at 90 mA g−1, 849.3 mAh g−1 at 900 mA g−1, and can be employed as excellent anode material for high energy-density lithium ion battery.

► The key trick is to use crystal water as the water phase in the water/oil system. ► As-obtained hollow sphere is made up of Fe3O4C nanocrystals. ► One hole is found on the surface of as-obtained hollow sphere. ► Unique hierarchical structure results in excellent cell performances.