Solvent-assisted molten salt process: A new route to synthesise α-Fe₂O₃/C nanocomposite and its electrochemical performance in lithium-ion batteries

Nanostructured α-Fe₂O₃ was synthesised by a simple molten salt process using FeCl₂·4H₂O as a starting material and LiNO₃-LiOH·H₂O-H₂O₂ as a eutectic mixture at 300 °C. To synthesise α-Fe₂O₃/C composite, both α-Fe₂O₃ and malic acid were dispersed together in toluene, where malic acid was used as a carbon source. The morphology and microstructure of both compounds were confirmed by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. Electrochemical testing, including constant current charge-discharge and cyclic voltammetry (CV), was carried out. The α-Fe₂O₃/C composite anode exhibited much better electrochemical performance than the bare α-Fe₂O₃. The discharge capacities of the composite were measured to be 2112 mAh g^-1 at C/2 after 100 cycles and 584 mAh g^-1 at 20 C after 10 cycles. The superior electrochemical performance of α-Fe₂O₃/C composite can be mainly attributed to the combined effects of the nanostructure, the carbon layering on the α-Fe₂O₃ nanoparticles, and the porous ultra-fine carbon matrix, where the three factors would contribute to provide high electronic conductivity, reduce the traverse time of electrons and lithium-ions, and could also prevent high volume expansion of the anode film during cycling. Our results indicate that the prepared α-Fe₂O₃/C nanocomposite is a very promising anode material for Li-ion power batteries. © 2010 Elsevier Ltd.