The Preparation And Properties Of ?"-Al₂O₃/BaTiO₃ Series Super-capacitor

Super-capacitor is a new type of energy storage device which has several advantages such as long cycle large energy storage, fast charge and discharge rate, long cycle life, high power density, good stability, etc. It has been widely used in various types of electronic equipment and new energy automotive industry, can effectively alleviate energy crisis and environmental issues. Currently, the most mature technology of super-capacitor is the super-capacitor of which the electrolyte is liquid state. Most research has focused on the electrolyte and the electrode material. But the liquid state electrolyte limits the expansion of super-capacitor's performance, its operating voltage and its operating temperature range are limited. Therefore, the major research of this paper focuses on fast ion conductor as a solid state electrolyte, and the solid-state super-capacitor is prepared to break through the bottleneck of the operating voltage and the operating temperature range to improve the overall performance of the device.The major works of this paper include powder synthesis, materials characterization, sample preparation and the test of electrochemical properties. Through the analysis of test results, the conclusions can be obtained. Specific results are as follows:1. The nano-powder of ?"-Al₂O₃ which is solid electrolyte material and Ba Ti O₃ which is dielectric material are synthesized through high-energy ball milling process. Then they are characterized.2. Through pressing process,using the aluminum foil as a collector, solid super-capacitor samples of ?"-Al₂O₃, Ba Ti O₃ and both mixed powder in different proportions were prepared.3. The electrochemical properties of samples are tested at room temperature and high temperatures, their operating voltage ranges of solid super-capacitor samples are broadened?-6V⁶V?. Wherein, the best performance of the sample is AB0.67, i.e. the optimum molar ratio of the mixed material is n?Ba Ti O₃?:n'??"-Al₂O₃?=2:3=0.67, of which specific capacitance reaches 95.15 m F/g, energy density reaches 1.93Wh/kg, and power density reaches 456.72W/kg.4. Through the electrochemical measurement at elevated temperature, it is verified that, the sample, AB0.67 still has good performance under 320?, having a specific capacitance 168.05 m F/g, an energy density 3.361Wh/kg, and a power density 2419.92W/kg at a high temperature. The analysis of the equivalent circuit of impedance frequency measurement prove the intervention of fast ion conductor materials ?"-Al₂O₃ making the operating voltage and the operating temperature range of the super-capacitor has been greatly improved. Thus, the performance of the device is improved.