Facile morphology-controlled synthesis of Co3O4 nanostructure on carbon cloth and their morphology-dependent pseudocapacitive performances

Tailoring the morphology and size of metal oxide by a facile synthetic method is challenging. In this paper, we in situ synthesized Co3O4 with different morphologies and sizes (nanosheets, nanowires, nanowire-clusters, rhombus-like thick round nanosheets) on carbon cloth by a facile hydrothermal reaction. The morphologies of Co3O4 were controlled by simply varying the mole ratio of NH4F to cobalt salt in the reaction solution. The effects of the morphologies of Co3O4 on its electrochemical performances were compared, and the results reveal that the nanowire-clusters Co3O4 exhibits the best electrochemical performance among all types of Co3O4, including a high specific capacitance of 621.8 F g−1 at 1 A g−1, outstanding rate capability and superior cycling stability of 90.6% retention over 3000 cycles. Also, its asymmetric supercapacitor (activated carbon as negative electrode) could deliver a high energy density of 17.92 Wh kg−1 at 1499.91 W kg−1, demonstrating a great potential for supercapacitor applications. This work provides a novel morphology-controllable synthesis approach to better understand the morphology effect on the electrochemical properties of Co3O4.