Soft template PEG-assisted synthesis of Fe3O4@C nanocomposite as superior anode materials for lithium-ion batteries

Carbon-encapsulated Fe3O4 composites were successfully fabricated via hydrothermal method and examined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The Fe3O4@C nanocomposite as an anode material with novel structure demonstrated excellent electrochemical performance, with enhanced specific reversible capacity (950 mAh/g at the current density of 50 mA/g after 50 cycles), remarkable rate capability (more than 650 mAh/g even at the current density of 1,000 mA/g) and good cycle ability with less capacity fading (2.4% after 50 cycles). Two factors have been attributed to the ultrahigh electrochemical performance: Firstly, the 30- to 50-nm spherical structure with a short diffusion pathway and the amorphous carbon layer could not only provide extra space for buffering the volumetric change during the continuous charging-discharging but also improve the whole conductivity of the Fe3O4@C nanocomposite electrode; secondly, the synergistic effects of Fe3O4 and carbon could avoid Fe3O4 direct exposure to the electrolyte and maintain the structural stabilization of Fe3O4@C nanocomposite. It was suggested that the Fe3O4@C nanocomposite could be suitable as an alternative anode for lithium-ion batteries with a high application potential.