9. Carbon Nanotube as Electrode Materials for Supercapacitors

High-performance supercapacitors are promising candidates for future energy storage devices for alternative power sources. Carbon nanotubes (CNTs) are considered as potential electrode materials for supercapacitors due to their superior electrical conductivity, high electrochemical stability, good mechanical properties, high specific surface area, and so on. Both single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) have been considered for electrochemical supercapacitor electrodes due to their unique properties like novel structure, narrow distribution of size in the nanometer range, highly accessible surface area, low resistivity, and high stability. The specific capacitance of CNTs mainly originated through the electric double-layer capacitor (EDLC) mechanism. Therefore, the supercapacitive performance of CNTs mainly depends on the physical properties, such as specific surface area, electrical conductivity, which are related to the synthesis and post-treatment methods of them. This chapter mainly emphasizes on the recent progress and development of the use of CNTs as supercapacitor electrodes through fabrication and post-treatment techniques.