Carbon coated Fe_3O_4 hybrid material prepared by chemical vapor deposition for high performance lithium-ion batteries

摘要

A hybrid material of carbon coated Fe_3O_4 (Fe_3O_4@C) is synthesized by chemical vapor deposition method using Fe_2O_3 as starting material and acetylene as carbon source. The obtained material is Fe_3O_4 spheres of ～400 nm coated by thin carbon layer with a thickness of ～10 nm. As an anode material for lithium ion batteries, Fe_3O_4@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 Fe_2O_3 and commercial Fe_3O_4 of the same size. In addition to the comparison of electrochemical impedance spectra of the Fe_2O_3, Fe_3O_4 and Fe_3O_4@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 Fe_3O_4 spheres.