Studies of nano‐sized Co3O4 as anode materials for lithium‐ion batteries

The structural evolution of the Co3O4 fine powders prepared by rheological phase reaction and pyrolysis method upon different temperature has been investigated using X‐ray diffraction (XRD) topography. The electrochemical performance of Co3O4 electrode materials for Li‐ion batteries is studied in the form of Li/Co3O4 cells. The reversible capacity as high as 930 mAh/g for the Co3O4 sample heat‐treated at 600 °C is achieved and sustained over 30 times charge‐discharge cycles at room temperature. The detailed information concerning the reaction mechanism of Co3O4 active material together with lithium ion is obtained through ex‐situ XRD topography, X‐ray photoelectron spectroscopy (XPS) analysis and cyclic voltammetry (CV) technique. And it is revealed that a “two‐step” reaction is involved in the charge and discharge of the Li/Co3O4 cells, in which Co3O4 active material is reversibly reduced into xCoO(3 ‐ x)CoO and then into metallic Co.