Carbon Nanotube-Based Supercapacitor Electrode for Energy Storage Applications

Supercapacitors are high-energy and high-power capacitors which bridge the gap between electrostatic capacitors and batteries as energy storage devices. Supercapacitor electrodes require porous surfaces with high surface area, which makes carbon nanotube (CNT) forests an appropriate candidate for electrode material. The growth of CNT forest over a suitable current collector is a sophisticated process requiring fine-tuning of various growth parameters. Also, the as-grown CNTs are hydrophobic and their wettability must be improved before use as supercapacitor electrodes. In this paper, the fabrication of a CNT electrode on carbon paper using catalyst dip-coating technique and Chemical Vapor Deposition (CVD) is discussed in detail. The dipping time is varied between 15 and 60 min to vary the catalyst coating thickness. The various factors that affect the growth mechanism are also elaborated. The fabricated electrode is electrochemically characterized to evaluate the capacitance. The capacitance is found to lie between 50 and 150 F/g.