The Properties Of Supercapacitors Based On Cobalt Metal Oxide

Energy storage device, especially supercapacitor, has been played a more important role in daily life, such as electronic device, transportation and so on. In this paper, we used the cobalt metal oxides as the electrode materials, we explored the controllable growth of these materials in large areas, also we designed the structures of the electrode and device. The main research results obtained can be summarized as following:(1)3D urchin-like NiCo2O4nanostructures were synthesized on a large scale via a simple hydrothermal method free of any template and catalyst. Studies found that urea played an important role to determine the morphology of the products and a "rods-to-straw-bundles-to-urchins" mechanism was proposed. In three-electrode system, the prepared NiCo2O4urchins exhibited superior specific capacitance of1650and1348F/g at current densities of1and15A/g, respectively. The results have obvious advantages compared with related reports. The electrochemical properties demonstrated the urchin NiCo2O4has high specific capacitance, excellent cycling stability and rate stability, indicating the urchin NiCo2O4has good electrochemical performance, and the method of synthesis NiCo2O4has a certain reference to other materials.(2) In order to improve the application of the supercapacitor, we used the flexible Ni foam as the substrate to synthesis NiCo2O4nanostructure directly. The electrode has a high specific capacitance of2681F/g at2A/g in the three-electrode system. The as-fabricated symmetric sueprcaapcitors have excellent electrochemical performance with a high cell areal capacitance of161mF/cm2at1mA/cm2. Good electrochemical performance stability was obtained when the device was under harsh mechanical conditions including both twisted and bent states. Our work here opened up opportunities for the device configuration for energy-storage devices in the future wearable electronic area and many other flexible, lightweight and high performance functional nanoscale devices.(3) We synthesized CUCo2O4nanowire arrays on carbon cloth on a large scale, to boost the electrochemical utilization and area-specific capacitance, core-shell CuCo2O4@MnO2heterostructured nanowire arrays on carbon fabric are synthesized. The prepared electrode has a high cell-specific capacitance, several times higher than that of CUCo2O4nanowire, at a current density of1.25A/g with excellent rate capability in aqueous electrolyte. The flexible, all-solid-state symmetrical supercapacitor is fabricated using PVA/KOH electrolyte. It delivers a high electrochemical performance and good stability in different bent states. These results suggest that the as-prepared CuCo2O4@MnO2/carbon fabric composite architecture is very promising for next-generation high-performance supercapacitors, and this work opens up a novel design of advanced integrated-array electrode materials for high-performance supercapacitors.(4) We synthesized NiCo2O4nanosheets on Ni wire for the first time, and characterized the morphology and crystal structure. Coaxial-type flexible fiber supercapacitor by using NiCo2O4nanosheets was successfully developed. Our coaxial-type fiber supercapacitor has a high performance compared with the parallel fiber device. The volume capacitance of the fiber-shaped supercapacitor researched10.3F/cm3at a current of0.08mA and outstanding cycling stability. An energy density of1.44mWh/cm3and a power density of up to17W/cm3were also obtained for the fiber supercapacitor, which are almost48-fold higher than the previous value. Due to the less report for the relevant work, our work has the original innovation and good role in promoting the structure design for micro supercapacitor.