Hematite nanoflakes as anode electrode materials for rechargeable lithium-ion batteries

Hematite (α-Fe2O3) nanoflakes and nanocubes were synthesized by liquid–solid-solution method and their properties as anode electrode materials for rechargeable Li+-ion batteries were measured. When changing the water to ethanol volume ratio in the synthesis system, the nanocrystals can be changed from α-Fe2O3 to α-FeOOH, with shapes being tuned from nanoflakes to nanocubes, non-uniform particles and nanowires. When assembled as the anode electrode materials in rechargeable Li+-ion batteries, the hematite nanoflakes showed one more plateau in the first discharge progress of the voltage–composition curves than hematite nanocrystals with other shapes in the literature. X-ray diffraction, high-resolution transmission electron microscope and electrochemical data showed that this extra plateau came from the formation of Li2Fe3O4 nanoclusters and amorphous Li2O. This experiment showed that like sizes, shapes of nanocrystals may also affect the detailed electrochemical progress.