Novel secondary assembled micro/nano porous spheres ZnCo₂O₄ with superior electrochemical performances as lithium ion anode material

In this work, novel secondary assembled micro/nano porous spheres ZnCo₂O₄ were firstly prepared by combining the hydrothermal method with post-synthesis calcinations. The structure and morphology of the obtained powder were characterized by x-ray powder diffraction and field emission-scanning electron microscopy. As the anode material of lithium-ion half-cells, the as-prepared ZnCo₂O₄ delivered a very high capacity, extra cycling stability and excellent rate capability. A discharge capacity of 950 mAh g⁻¹ with up to 99.7% retention corresponding to the second cycle at 0.1 C was achieved after 90 cycles, which was an improved cyclability over previous reports. The higher current charge–discharge and electrochemical impedance spectroscopy data indicate that the material's integrity was maintained. Therefore constructing the secondary assembled 3D micro/nano structure is an effective strategy to obtain the superior electrochemical performances. (paper)