Carbon nanotube based nanocomposites for miniaturized supercapacitor applications
| Autor: | Wei-Chuan Fang, 方偉權 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 In this dissertation work, we report a simple and efficient route to prepare nanocomposites with well-dispersed ruthenium oxide nanoparticles (NPs) on a vertically aligned nitrogen-containing carbon nanotube (CNx NT) array directly grown on Si substrates. It is found that uniform ruthenium oxide NPs can be formed around the sidewalls of CNx NTs over a large area with simple sputtering method, without using any wet chemical pretreatments or metal organic precursors. Cyclic voltammetry (CV) measurement suggests a superior specific capacitance of 1380 F/g (RuO2-based mass) at 600 mV/s. More importantly, this RuO2-CNTs composite exhibits an ideal capacitive behavior at an extremely high scan rate of up to 600 mV/s for 5000 cycles, and the charging-discharging capacity can be as high as 23 mA/cm2. Besides, effects of nitrogen doping on the enhancement in capacitive performance of RuO2 coated carbon nanotubes are also investigated. A significant increase in the measured capacitance has been obtained for the nitrogen-doped sample. The function of nitrogen doping is to create more nucleation sites on the sidewalls of CNTs for RuO2 NPs attachment. So far, an optimal scan rate of 2000 mV/s has been obtained. Definitely, nitrogen incorporation indeed plays an important role in the ultra fast charging-discharging capacitive behaviors of RuO2-coated carbon nanotubes. Therefore, the reported RuO2-CNxNT nanocomposites are suitable for miniaturized energy storage devices with superior capacitive performances. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|