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.