High rate capability of Fe/FeO/Fe3O4 composite as anode material for lithium-ion batteries

Fe/FeO/Fe₃O₄ composite was synthesized by a simple solid method using ferric citrate and phenolic resin as raw materials. The reaction processes of raw materials mixture were characterized by thermogravimetric analysis (TGA) under nitrogen. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the structure and morphology of the products. The results showed that the obtained material was octahedral Fe/FeO/Fe₃O₄ composite with a size of 2-4 μm. The electrochemical performances of Fe/FeO/Fe₃O₄ composite as anode material were also evaluated, which exhibited a stable specific capacity of 260.3 mAh g^-1 and an ideal initial coulombic efficiency of 90.8% in the range of 0.05~3 V at the 5C rate. A good rate capacity of Fe/FeO/Fe₃O₄ composite electrode was also shown by the charge-discharge testing even at the rate of 60C. The better rate capability of Fe/FeO/Fe₃O₄ electrode could be measured in higher temperature.