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 degrees C, respectively. The XRD patterns of both the samples corresponded to the pure crystal structure of b-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).