| Energy storage devices are receiving extensive attention in recent years due to the increasing demand of energy. Super-capacitor is one of the energy storage devices with high specific power density and wide applications in electronic vehicles, commercial mobile electronics, and military devices. Carbon based materials are widely used in making Electrochemical Double Layer Capacitor (EDLC) or super-capacitor for their excellent porous nature along with their electron transport capability. By increasing the specific surface area of the porous carbon materials, specific capacitance of the super-capacitor can be significantly improved. Graphene, a newly discovered material, has been incorporated in making super-capacitor electrodes for its extraordinary electrical properties with highly conductive specific surface area. Recently, nanowire/graphene hybrids have been developed for the enhancement of super-capacitor performance; however, all previous efforts employed nanowires on graphene in a randomly distributed fashion, which limits the performance. Therefore, this thesis demonstrates a new approach by growing aligned nanowire on graphene aerogel to further improve the performance. This nanowire/graphene aerogel hybrid not only uses the high surface area of the graphene aerogel but also increases the specific surface area for electrode-electrolyte interaction. Therefore, this new nanowire/graphene aerogel hybrid electrode material could enhance the specific capacity. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Atomic Force Microscopy (AFM) are used for materials characterization. Potentio-galvanostat and LCR meter are used for measuring electrical performance of the super-capacitor. The testing results have shown that with graphene/nanowire hybrid electrodes, the performance of the super-capacitor could be significantly improved. |
