Electrochemical oxidation of multi-walled carbon nanotubes and its application to electrochemical double layer capacitors

• Published in: Electrochemistry communications Vol. 7; no. 3; pp. 249 - 255
• Main Authors: Ye, Jian-Shan, Liu, Xiao, Cui, Hui Fang, Zhang, Wei-De, Sheu, Fwu-Shan, Lim, Tit Meng
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.03.2005; Amsterdam Elsevier Science; New York, NY
• Subjects: Applied sciences; Capacitors. Resistors. Filters; Carbon nanotubes; Electric double layer capacitor; Electrical engineering. Electrical power engineering; Electrochemical oxidation; Electrodes; Exact sciences and technology; Multi-walled carbon nanotubes; Various equipment and components; Electrodes; Carbon nanotubes; Electric double layer capacitor; Multi-walled carbon nanotubes; Electrochemical oxidation; Performance evaluation; Energetic efficiency; Electrochemical double layer; Oxidative degradation; Electrolytic capacitor; Electrode material; Surface area; Specific capacity
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2005.01.008

The effect of electrochemical oxidation in 0.2 M HNO 3 for multi-walled carbon nanotubes (MWNTs) on the performance of electrochemical double layer capacitors (EDLCs) was studied. Scanning electron microscope and transmission electron microscope images reveal that electrochemical oxidation increases the specific area of MWNTs by cutting off the nanotube tips. Cyclic voltammetry and constant current charging/discharging was used to characterize the behavior of EDLCs of the oxidized-MWNTs in 1.0 M H 2SO 4. The specific capacitance of the oxidized-MWNTs was remarkably improved. The maximum specific capacitance of 335.2 ± 13.1 F g −1 ( n = 3) was obtained for the oxidized-MWNTs with open tips, which is 11 times than that of normal MWNTs (32.7 ± 7.1 F g −1). Electrochemical oxidation is hence an effective way to improve the performances of the MWNTs electrodes in EDLCs application.