Performance improvement of lithium ion batteries using magnetite–graphene nanocomposite anode materials synthesized by a microwave-assisted method

• Fe3O4/graphene nanocomposites were synthesized by a microwave-assisted method.
• The nanocomposites improved the performance in the anode of Li ion batteries.
• The well-dispersed Fe3O4 nanoparticles can effectively prevent graphene restacking.
• Fe3O4 particles sandwiched by graphene sheets are resistant to pulverization.
• High capacity of 911 mAh/g was obtained after 30 cycles at 100 mA/g current density.

Fe3O4/graphene nanocomposites were synthesized by a microwave irradiation method. We prepared Fe3O4/graphene nanocomposites with different microwave powers – 200, 600, and 1000 W. The structure and morphology of the Fe3O4/graphene nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM). This composite structure not only prevented the loss of active sites for lithium ion intercalation due to graphene restacking, but also alleviated the volume change and the subsequent pulverization of Fe3O4 particles during the lithium ion insertion/extraction processes. In addition, the excellent conductivity of graphene can enhance the electron transport in the electrodes, thereby improving the capacity at high current densities. The electrochemical measurements showed that our Fe3O4/graphene nanocomposites synthesized at 1000-W microwave power exhibited a specific capacity as high as 911 mAh/g at a current density of 100 mA/g after 30 cycles.

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