Enhanced cycling performance of an Fe⁰/Fe₃O ₄ nanocomposite electrode for lithium-ion batteries

We demonstrate the formation of a highly conductive, Fe⁰/Fe ₃O₄ nanocomposite electrode by the hydrogen reduction process. Fe₂O₃ nanobundles composed of one-dimensional nanowires were initially prepared through thermal dehydrogenation of hydrothermally synthesized FeOOH. The systematic phase and morphological evolutions from Fe₂O₃ to Fe₂O ₃/Fe₃O₄, Fe₃O₄, and finally to Fe/Fe₃O₄ by the controlled thermochemical reduction at 300 °C in H₂ were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM). The Fe/Fe ₃O₄ nanocomposite electrode shows excellent capacity retention (∼540mAhg^-1 after 100 cycles at a rate of 185mAg ^-1), compared to that of Fe₂O₃ nanobundles. This enhanced electrochemical performance in Fe/Fe₃O₄ composites was attributed to the formation of unique, core-shell nanostructures offering an efficient electron transport path to the current collector.