Preparation of 3D hierarchical porous Co3O4 nanostructures with enhanced performance in lithium-ion batteries

Three-dimensional hierarchical Co3O4 microspheres assembled by well-aligned 1D porous nanorods have been synthesized by hydrothermal methods with the help of CTAB and subsequent heat treatment. The morphology and compositional characteristics of the hierarchical Co3O4 microspheres have been investigated using different techniques. Based on the SEM and TEM analyses, the growth direction of the nanorods is in the [110] direction. The hierarchical Co3O4 microspheres have a comparatively large Brunauer–Emmett–Teller surface area of about 50.2 m2g−1, and pore size distribution is mainly concentrated at 12 nm. On the basis of the time tracking experiment, a possible growth mechanism has been proposed. It demonstrates that the overall mechanism includes nucleation, oriented growth and self-assembly processes. These hierarchical Co3O4 microspheres provide several favorable features for Li-ion battery applications: (1) large Brunauer–Emmett–Teller surface area, (2) porous structure, and (3) hierarchical structure. Therefore, measurement of the electrochemical properties indicates that the specific capacity can maintain a stable value of about 1942 mA h g−1 at a current of 100 mA g−1 within 100 cycles.