Carbon nanotube thin films have been successfully fabricated by the electrophoretic deposition technique. The supercapacitors built from such thin film electrodes have a very small equivalent series resistance, and a high specific power density over 20 kW kg −1 was thus obtained. More importantly, the supercapacitors showed superior frequency response. Our study also demonstrated that these carbon nanotube thin films can serve as coating layers over ordinary current collectors to drastically enhance the electrode performance, indicating a huge potential in supercapacitor and battery manufacturing.

TitleHigh power density supercapacitors using locally aligned carbon nanotube electrodes Abstract A new form of thin films formed by multi-walled carbon nanotubes exhibiting high packing density and local alignment were fabricated using a highly concentrated colloidal suspension of carbon nanotubes. Electrical double layer capacitors built from these film electrodes exhibited a close to rectangular cyclic voltammogram even at a high scan rate of 1000 mV s −1 , and produced very high specific power density of about 30 kW kg −1 , ideal for surge-power delivery applications. The preparation procedure is very simple, and does not require any binders. It has potential for highly efficient manufacturing of high power density supercapacitors and other similar electronic devices.

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A new and feasible method to prepare long and well-oriented SWNTs on substrates in large scale is developed by applying a floating catalyst chemical vapor deposition (CVD) process. The catalysts for SWNT growth come from the decomposition of iron pentacarbonyl (Fe(CO)5) formed in situ from the reaction of iron powder and carbon monoxide gas. The growth of SWNTs is found to happen both on the substrate and in the gas flow. Both long and short nanotubes are formed on the substrates but only the long SWNTs are aligned by gas flow. The growth direction and the density of the long SWNTs can be easily controlled. In addition, long SWNTs can be cut and patterned using photolithography and water plasma etching techniques, offering a way to prepare patterned SWNTs with controllable orientation, density and lengths for various applications.