Superior cycling and rate performances of rattle-type CoMoO4 microspheres prepared by one-pot spray pyrolysis

Abstract

Rattle-type CoMoO₄ and CoMoO₄–carbon composite microspheres were prepared by one-pot spray pyrolysis at temperatures of 850 and 700 °C, respectively. The XRD patterns of both the samples corresponded to the pure crystal structure of β-CoMoO₄. The CoMoO₄–carbon composite microspheres exhibited broad diffraction peaks with relatively lower intensities, when compared to those of rattle-type CoMoO₄ microspheres. This indicates the poor crystallinity of the carbon composite powders, despite the similar preparation conditions. In the initial cycles, the rattle-type CoMoO₄ microspheres and CoMoO₄–carbon composite microspheres delivered discharge capacities of 1221 and 1245 mA h g⁻¹, respectively at a current density of 500 mA g⁻¹, and charge capacities of 1019 and 896 mA h g⁻¹, respectively, corresponding to Coulombic efficiencies of 83 and 72%, respectively. After 150 cycles, the discharge capacities of the rattle-type and carbon composite microspheres were 1065 and 833 mA h g⁻¹, respectively, and the corresponding capacity retentions measured after the first cycles were 100 and 90%, respectively. The morphology of the rattle-type CoMoO₄ microsphere was maintained, despite repeated Li⁺ insertion and extraction processes, even at a high current density of 500 mA g⁻¹.