The Synthesis Of Several RuO₂Nanomaterials And Their Supercapacitor Performances

We are living in an age of electrification; the ubiquitous use of electric energy has made its storage a very important issue. For example, the outbreak of the global energy crisis, resulting in natural energy power generation resources, such as wind energy, solar energy, tidal energy and hydro energy, have attracted more and more attention; and the intermittent caracteristics has made the energy conversion storage of such non-fuel energy increasingly important. Additionally, the first and foremost problem need to be solved of the extensive use of portable electronic equipments, electric motor vehicles, power backups is the mobile power sources. How to achieve efficient energy storage has become one of the most important science and engineering problems of the21st century, In China, it has been listed in the national long-term science and technology development Plan of China (2006-2020), and has become the most important cutting-edge technology in the long-term national development of the field of power sources.One important type of energy storage technologies is electrochemical energy storage which converts electrical energy to electrostatic energy or chemical energy to store. At present, the main two types of electrochemical energy storage devices are lithium ion battery and supercapacitor. Lithium-ion battery is currently the most perfect and widely used energy storage device. It has a high repeated utilization ratio of resources, and also has characteristics of high capacity, small size, easy to recycle and a low level of environmental pollution; and is widely used in electronic industry. Another main type of electrochemical energy storage device is supercapacitor. In addition to the above characteristics of lithium-ion battery, the most prominent advantage of supercapacitor is its high rate performance and the excellent cycling stability. One valid application of supercapacitor is the instantaneous power energy release and fast storage during the motor vehicle start-up and braking process. With the gradual increase of the overall performance of the supercapacitor, its application in real life will be more extensive.In this thesis, we mainly focus on exploring the high-performanced supercapacitor electrode nanomaterials. In our work, we try to simplify the experimental process, increase the specific surface area and improve the electron/ion transfer rate of the electrode material to promote their supercapacitor performance. The details are as follow:1. Uniform RuO2nanotube was successfully prepared. Cobalt hydroxide alkaline nanowire arrays, prepared on Ti substrate through simple low-temperature hydrothermal method, were used as template to obtain RuO2nanotubes by low-temperature water bath and the followed template erosion. SEM, TEM, XRD, EDX methods were used to characterize the morphology, structure and composition of the material. When the prepared RuO2nanotubes were used as the supercapacitor electrode material, relatively high specific capacitance and good cycling stability were obtained.2. RuO2nanomaterial with different morphologies were prepared on the conductive metal substrate by one step hydrothermal method. Two different kinds of RuO2nanostructures were prepared on Ti substrate by hydrothermal process with different kinds of surfactants added. SEM, TEM, XRD, EDX methods were used to characterize the morphology, structure and composition of the material. The morphology formation mechanisms of the material were discussed through the contrast of materials obtained with different reaction time. When the two kinds of prepared RuO2nanomaterial were used as the supercapacitor electrode material, the reasons between their different supercapacitor performances were simple analyzed.3. Co3O4/RuO2nanocomposite was synthetized. Flower-like Co3O4nanostructure was prepared through hydrothermal method, after annealed, RuO2nanoparticles were deposited on it, then the Co3O4/RuO2nanocomposite was obtained. SEM, TEM, XRD, EDX methods were used to characterize the morphology, structure and composition of the material. When the prepared Co3O4and Co3O4/RuO2were used as the supercapacitor electrode material, the results showed that the supercapacitor performance of the Co3O4/RuO2nanocomposite was better than that of Co3O4nanomaterial. And the supercapacitor performances of nanocomposite obtained with different concentration of precursor showed that electrochemical performance of the nanocomposite proportional to the concentration of the precursor within a certain range. Finally, through contrast, a simple analysis of the synthesis mechanism as well as the reasons of their different performances is revealed.