Facile synthesis of Fe2O3/MWCNT composites with improved cycling stability

Abstract

In this study, Fe₂O₃/multi-walled carbon nanotube (Fe₂O₃/MWCNT) composites were synthesized via vacuum solution absorption and subsequent calcination treatment. The amount of Fe₂O₃ and MWCNT components, crystalline structure, morphology and electrochemical performance of the as-prepared material were characterized by thermo-gravimetric (TG) analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) method, energy dispersive spectrometry (EDS) and charge–discharge tests. Results show that Fe₂O₃ nano-particles, with a diameter of about 23 nm, loaded in the void space in the intertwined MWCNT matrix or on the MWCNT homogeneously. The as-obtained Fe₂O₃/MWCNT composites have a relatively small BET surface area, pore size and pore volume compared to that of pure MWCNT. Electrochemical measurements show that the Fe₂O₃/MWCNT composites exhibit a high reversible capacity of 1026 mA h g⁻¹ after 50 cycles at a charge–discharge rate of 0.2 C. The improved performance may be ascribed to the nano-sized Fe₂O₃ with a faster Li⁺ diffusion coefficient which can release the volume expansion effectively. On the other hand, the MWCNT can act as a buffering matrix and electron conductors in the composites.