α-Fe2O3 hollow microspheres assembled by ultra-thin nanoflakes exposed with (241) high-index facet: Solvothermal synthesis, lithium storage performance, and superparamagnetic property

Hierarchical α-Fe2O3 hollow microspheres are synthesized through a convenient and effective solvothermal method. The α-Fe2O3 hollow microspheres have a mean diameter of 1 μm and they are composed of ultra-thin nanoflakes with an average thickness of only 5 nm. More importantly, the primary α-Fe2O3 nanoflakes are preferentially enclosed by (241) high-index facet. When the α-Fe2O3 hollow microspheres are served as anodes for lithium-ion batteries, their first discharge capacities is 1749.1 mAh g−1 at 0.1 A g−1, and the corresponding values are 914.0, 628.7, and 420.5 mAh g−1 at high current densities of 0.2, 0.5, and 1 A g−1, respectively. The improved electrochemical performance can be attributed to the synergistic effect of the hierarchical hollow microstructure, exposed high-index (241) facet, and thin primary nanoflakes. Additionally, the α-Fe2O3 hollow microspheres have superparamagnetic properties due to the ultra-thin thickness of the primary α-Fe2O3 nanoflakes.