Facile one-pot fabrication of α-Fe₂O₃ nano-coffee beans by etching along [001] direction for high lithium storage

It is a great challenge to finely tune the morphology of iron oxides for energy storage. In this work, we introduced a facile hydrothermal method to obtain single crystalline hematite (α-Fe₂O₃) nano-coffee beans (NCBs) with the assistance of acetic acid. Interestingly, α-Fe₂O₃ nanostructures with this special morphology were formed under the effect of Ostwald ripening and oriented etching of H⁺ ions along [001] direction, which could be proved by the scanning electron microscope /transmission electron microscope and X-ray diffraction. After calcination at high temperature, the as-prepared α-Fe₂O₃ NCBs were used as potential anode materials, showing a very high reversible capacity of 810 mA h g⁻¹ (0.2 C), excellent cycling stability, and high-rate performance for lithium storage. Hence, in virtue of the good performances, the structural design of nanomaterials would be promoted in the fabrication of electrode materials for lithiumion batteries.