Study On The Electrode Material Of Supercapacitor

Supercapaitors have been recongnized as new electrochemical energy storage devices which performance between the rechargeable batteries and the typical dielectric capacitors. The typical rechargeable batteries can provide high energy densities, but the low power densities. The typical dielectric capacitors can provide high power densities, but the low energy densities.Studies on supercapaitors are main focus on the preparation of high performance electrode materials now. With Ni(OH)2, NiO and activated carbon ball as electrode materials for supercapacitors, this dissertation has reasearched on the electrode materials perparation and capacitive property. The eletrode materials have been characterized by X-ray diffraction, transmission electron microscope. The main results are follows.Ni(OH)2 was prepared by hydrothermal method, the results of XRD indicate that the sample isβ-Ni(OH)2. Supercapacitor properties were studied by cyclic voltammetry and constant-current charge-recharge. The experimental results show that Ni(OH)2 has typical Faraday capacitor characteristics. The maximum specific capacitance of Ni(OH)2 is 312.3 F/g and it has good cycling performance.NiO powder was prepared through the thermal decomposition of Ni(OH)2 at 300℃which was used as a precursor. The nickel oxide electrode has been fabricated and NiO as the active material. Supercapacitor properties were studied by cyclic voltammetry, impedance spectrum and constant-current charge-recharge. A specific capacitance of 215.6 F/g was achieved when using nickel oxide electrode at the current density of 10 mA/cm2 and 7 mol/L aqueous KOH as an electrolyte.The activated carbon ball was prepared from sucrose and was activated in a high temperature. The effect of activating temperature on the specific capacitance of activated carbon ball was studied. The relationship between the pore structure, surface area and specific capacitance of activated carbon ball were discussed. The electrochemical characterization was also conducted with cyclic voltammetry and impedance methods. The reasults show that the specific capacitance of activated carbon ball obviously increased after activation.