Synthesis of carbon-coated Co3O4 composite with dendrite-like morphology and its electrochemical performance for lithium-ion batteries

Carbon-coated Co3O4 microparticles (Co3O4@C) with dendrite-like morphology are prepared by a low-temperature hydrothermal method and subsequent C2H2 chemical vapor deposition (CVD) for the first time. The synthesized precursor Co3O4 has a size of 8–10 μm, which is assembled by lots of aligned Co3O4 wire with 4–5 μm in length. After carbon coating, Co3O4 microparticles were proved to be coated in amorphous carbon of ~10 nm. A plausible formation process of the dendrite-like Co3O4 and Co3O4@C is proposed based on the morphology and structure characterizations of the materials. As an anode material for lithium-ion batteries, the Co3O4@C composite electrode exhibits higher reversible capacity and better cycling performance than the unmodified Co3O4 electrode. The reversible capacity of the Co3O4@C composite after 40 cycles is 500 mAh g−1, much higher than that of Co3O4 (148 mAh g−1). Electrochemical impedance spectra and cyclic voltammogram indicate that the carbon layer coated on Co3O4 by CVD can improve the electrochemical activity and enhance the reversibility of Co3O4 during charge/discharge cycles.