One-step synthesis of CoO anode material for rechargeable lithium-ion batteries

We report a fast method to prepare cobalt oxide (CoO) nanoparticles via urea-assisted auto-combustion synthesis at 300 °C without any post-heat treatment. The structure and morphology were analyzed by synchrotron X-ray diffraction, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy. As-prepared cobalt oxide is cubic, with spherical particle size in the range of 20–30 nm. Electrochemical measurements were performed using the as-prepared powders as the active material for a lithium-ion cell. As an anode for lithium-ion batteries, the nanoparticles electrode exhibited high discharge capacity and good cycling performance with 98% Coulombic efficiency. The nanoparticle electrode delivered a second reversible discharge capacity of 855.47 mA h/g and exhibited ∼66% of capacity retention (565.16 mA h/g) after 23 cycles. The enhancement of the electrochemical performance is attributed to the high specific surface area, good electric contact between the particles, and easier lithium ion diffusion.