Carbon coated Fe3O4 hybrid material prepared by chemical vapor deposition for high performance lithium-ion batteries

A hybrid material of carbon coated Fe3O4 (Fe3O4@C) is synthesized by chemical vapor deposition method using Fe2O3 as starting material and acetylene as carbon source. The obtained material is Fe3O4 spheres of ∼400 nm coated by thin carbon layer with a thickness of ∼10 nm. As an anode material for lithium ion batteries, Fe3O4@C shows an improved electrochemical performance in the reversible capacity and cycling stability, together with excellent rate capability. The performance is much better than the results obtained from bare Fe2O3 and commercial Fe3O4 of the same size. In addition to the comparison of electrochemical impedance spectra of the Fe2O3, Fe3O4 and Fe3O4@C electrodes before and after 50 charge/discharge cycles, a surface contrast of the three electrodes before and after cycling is systematically investigated to explore the influence of carbon layer on the electrochemical performance of the Fe3O4 spheres.