ZENG Xiaojun, DING Junqing, ZHANG Zuliang, ZHANG Xiaoye, SUN Liangliang
(Advanced Ceramic Materials Research Institute, School of Materials Science and Engineering, Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China)
Abstract: Supercapacitors exhibit high power density and long-term cycle life time in energy-power applications. Multi-component metal oxides are promising electrode materials for supercapacitors, due to their multivalent cations and diverse charge/discharge kinetics. However, it is difficult to control the morphology of multi-component metal oxides and the regulation methodsareusually too complicated. In this work, CoMoOx nanostructures were grown on the surface of nickel foam by using a simple one-step hydrothermal method. The controllable synthesis of Co0Mo1Ox ultra-thin nanosheets, Co1Mo2Ox interwoven nanosheets, Co1Mo1Ox nanoflowers and Co2Mo1Ox nanopillar structures was realized by adjusting the Co:Mo molar ratio. Among them, the unique structure of Co1Mo1Ox nanoflowers enabled high specific capacitance and excellent cycling stability, with a specific capacitance of as high as 1628.8 F•g−1 at a current density of 5 A•g−1, which is superior to numerous advanced Co/Mo-based electrode materials. The Co1Mo1Ox nanoflowers can still retain 93.5% of the specific capacitance after 2000 cycles of galvanostatic charge-discharge (GCD) cycling. In addition, asymmetric supercapacitors (ASCs) devices assembled with Co1Mo1Ox nanoflowers and activated carbon (AC) exhibited high energy density, delivering an energy density of 79.3 Wh•kg−1 at a power density of 4 kW•kg−1. This work provides a controllable synthesis strategy of multi-component metal oxide nanostructures and enriches self-supporting, binder-free, and high energy storage properties of electrode materials for pseudocapacitors.
Key words: CoMoOx nanostructures; controllable synthesis; high energy density; pseudocapacitor; asymmetric supercapacitors