α-Fe2O3 and Fe3O4 hollow nanospheres as high-capacity anode materials for rechargeable Li-ion batteries

alpha-Fe2O3 and Fe3O4 hollow nanospheres of size 30 +/- 2 nm were synthesized by using polymeric micelles as a soft template for the first time. The hollow nanospheres were thoroughly characterized by transmission electron microscope, superconducting quantum interference device, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis, cyclic voltammogram, and nitrogen sorption analyses. The alpha-Fe2O3 and Fe3O4 hollow nanospheres were used as anode materials in lithium-ion rechargeable batteries to investigate their electrochemical properties. The hollow particle-based electrodes exhibit high capacity, stable cycling performance, and good rate capability at different current densities. The alpha-Fe2O3 and Fe3O4 hollow nanospheres with nanosized shell domain favors fast lithium insertion/extraction processes during the repeated charge/discharges.