Syntheses of nano-sized Co-based powders by carbothermal reduction for anode materials of lithium ion batteries

Co oxide powders were synthesized by spray drying, calcining, and then ball milling. Nano-sized Co-based powders were then prepared by carbothermal reduction at 873 K, 1073 K, and 1173 K of the synthesized Co oxide powders. Then, the electrochemical properties of the electrodes made with the Co-based powders were examined to evaluate their suitability as anode materials for Li-ion batteries. It was reported that among Co, CoO, and Co₃O₄, Co₃O₄ had the best cycling performance. However, in this work, Co showed the best cycling performance. This means that the mechanisms of the cycling performance of CoO and Co which were synthesized by different heat treatment methods are different from each other. The initial discharge capacities of three electrodes made with the powders reduction-treated at 873 K, 1073 K, and 1173 K were similar and about 1100 mA h/g, respectively. However, the electrodes made with the powders reduction-treated at 873 K and 1073 K had the discharge capacities at the second cycle which were less than 50% of the discharge capacity of the electrode made with the powder reduction-treated at 1173 K. The electrode made with the powder reduction-treated at 1173 K had a discharge capacity of 750 mA h/g at the 20th cycle, demonstrating that this electrode had good cycling performance.