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

Abstract

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 (950mAh/g at the current density of 50mA/g after 50 cycles), remarkable rate capability (more than 650mAh/g even at the current density of 1,000mA/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.