α-Fe2O3 as an anode material with capacity rise and high rate capability for lithium-ion batteries

We report a simple molten salt method to prepare nanosize alpha-Fe2O3, as well as its electrochemical performance as anode material for lithium ion batteries. The structure and morphology were confirmed by Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. The as-prepared alpha-Fe2O3 is a rhombohedral phase of hematite with crystal size in the range of 20-40 nm. The electrochemical measurements were performed using the as-prepared powders as the active material for a lithium-ion cell. The nanosized alpha-Fe2O3 shows excellent cycling performance and rate capability. It also exhibits the feature of capacity increase upon cycling. The outstanding electrochemical performance of the alpha-Fe2O3 can be related to several factors, namely, the short Li+ diffusion length along the porous rhombohedral structures and the nanosized nature of the materials, which decreases the traverse time for electrons and Li+ ions, and reduces the volume expansion to some extent during charge/discharge reactions. (C) 2011 Elsevier Ltd. All rights reserved.