Studies On Preparation And Application Of Ordered Mesoporous Carbon/polyaniline Composites For Supercapacitor Electrode

In this thesis,the newest development in research of supercapacitors and the electrode materials of supercapacitor devices have been reviewed.Because ordered mesoporous carbon CMK-3 exhibit high specific area and highly ordered pore structure, three kinds of nanostructured composites were prepared by using CMK-3 as the supporter and an attempt was made to apply the mass active electrode materials for electrochemical capacitors.The main studies are as follows:1.The ordered mesoporous carbon CMK-3 was synthesized by using SBA-15 as surfactant-template.Chemically modified CMK-3 is prepared by wet-oxidative method in HNO3 solution. Structures, morphologies,pore size distributions and pore volumes of p-CMK-3 and m-CMK-3 have been systemically explored.The electrochemical capacitance characteristic of CMK-3 has also been systemically studied. The result shows that CMK-3 present amorphous structure and highly ordered pore structure with average pore size of among 2～8 nm.The CMK-3 with surface area of about 1206 m2/g and volume of about 1.38 cm3/g yields the best electric layered capacitance, i.e.about 145F/g. After chemically modified CMK-3 in HNO3 solution, the capacitance of CMK-3 has been improved greatly, the specific capacitance is up to 200 F/g.2.By using m-CMK-3 as template, a novel m-CMK-3/PANI composite was successfully prepared by in-situ chemical oxidative polymerization. The microstructure and supercapacitive behaviors of these composites were investigated through SEM, XPS,cyclic voltammetry, charge-discharge and impedance spectroscopy. The particles of PANI on m-CMK-3 with large space between ordered nanowires can be effective to obtain fully reversible and very fast redox behavior, which contribute to the pseudo-capacitance.The maximum SC of m-CMK-3/PANI composite (30 wt% m-CMK-3)was up to 489 F/g. As the support of m-CMK-3,its unique porous structure, large specific surface area and surface activity have played an important role in optimizing the structure of m-CMK-3/PANI composite, making active materials more dispersed as well as improving the availability of PANI and good cycle performance.3.In order to improve the power and energy performances and ameliorate the cycle stability of m-CMK-3/PANI composite electrode for supercapacitors, an electrochemical hybrid capacitor was successfully designed using m-CMK-3/PANI composite and m-CMK-3 as positive and negative electrodes,respectively. The discharge capacity of the hybrid capacitor reached 87.4F/g in a lmol/L H2SO4 electrolyte solution under a current density of 5mA/cm2 and a cell voltage of 1.4 V. The energy density of the hybrid capacitor reached 23.8Wh/kg with a power density of 206 W/kg. When the current density was increased from 5.0 to 50mA/cm2, the capacity of the hybrid capacitor in a 1mol/L NaNO3 electrolyte solution remained at about 80% and it showed excellent high rate charge-discharge performance. Furthermore, the m-CMK-3/PANI hybrid capacitors possessed high charge-discharge efficiency and good cycle performance.