[en] Carbon-composited ferroferric oxide (Fe₃O₄@C-1) was synthesized through a thermal decomposition of the chelate (Fe)₂(C₄H₄O₆)₃, which can be served as the sources for both Fe₃O₄ and carbon. After etching in hydrochloric acid (HCl) solution for 20 min, the pyrolytic Fe₃O₄@C-1 turned into Fe₃O₄@C-2 gaining a higher specific surface area and a better electrochemical performance. As anode materials for lithium-ion batteries, the Fe₃O₄@C-2 sample delivers a reversible capacity of 1047 mAh g⁻¹ at a current density of 200 mA g⁻¹ and remains the capacity at 837 mAh g⁻¹ after 200 cycles, while the capacity of the Fe₃O₄@C-1 electrode fades to only 94 mAh g⁻¹ after 200 cycles.