Improved electrochemical performance of Fe2O3 nanoparticles confined in carbon nanotubes

A hybrid material of carbon nanotube (CNT)-encapsulated Fe2O3 nanoparticles was prepared by immersing CNTs with two open ends in a Fe(NO3)(3) solution followed by thermal decomposition. It was found that the hollow core of the CNTs was filled with a homogeneous array of Fe2O3 nanoparticles with each nanoparticle being a single crystal. As an anode material of lithium-ion batteries, the Fe2O3-filled CNTs exhibited an improved electrochemical performance in terms of high reversible capacity, excellent cycling stability (811.4 mA h g(-1) after 100 cycles), and high rate capability, compared to that of pure Fe2O3. We attribute this superior electrochemical performance of the Fe2O3-filled CNTs to the small size of the Fe2O3 nanoparticles, the confinement effect of CNTs, sound electrical contact between these two components, as well as the good electrical conductivity and unique porous structure of CNTs that improve the electron and lithium ion transport ability of the anode.