Improved and Large Area Single-Walled Carbon Nanotube Forest Growth by Controlling the Gas Flow Direction

Abstract

A gas shower system was introduced to improve the growth of single-walled carbon nanotube (SWNT) forests by controlling the gas flow direction. Delivery of gases from the top of the forest enabled direct and precise supply of ethylene and water vapor to the Fe catalysts. As such, this approach solved one of the limiting factors of water-assisted chemical vapor deposition method (CVD), that is, delivery of the very small optimum water level to the catalysts. Consequently, this approach improved SWNT forests growth stability, uniformity, reproducibility, carbon efficiency (32%), and catalyst lifetime. With this improved growth, we could synthesize a 1 cm tall forest with 1 x 1 cm size. Also we employed this approach to grow an A4 size SWNT forest to highlight the scalability of water-assisted CVD.

Extracting the Full Potential of Single‐Walled Carbon Nanotubes as Durable Supercapacitor Electrodes Operable at 4 V with High Power and Energy Density

“…Although we have scientifi cally shown a practical reliable performance of SWNT electrodes far exceeding that of AC electrodes, for commercialization cost is a major consideration. We believe recent advances made in SWNT mass production [ 18 ] will reduce the cost by a factor of several hundred, thus eventually reaching a similar cost to AC.…”

“…[ 17 ] This fabrication process is scalable, as demonstrated by the recent development of large-area synthesis of SWNT forests. [ 18 ] For comparison, AC electrode sheets (density 0.6 g cm − 3 , area 1 cm 2 , thickness ca. 100 μ m) were also made by a conventional process, that is, mixing and kneading of AC powder (YP17: 1640 m 2 g − 1 ) with a binder (poly(tetrafl uoroethylene), PTFE) and a conducting agent (carbon black).…”

A super-growth method for single-walled carbon nanotube synthesis

“…12). [14] Various changes were made to the showerhead to evenly supply extremely minute amount of water to the catalysts on the substrate material. Next, the synthesis furnace was made vertical and the diameter was increased from 1 inch, to 2 inches, and then 4 inches.…”

Confocal Microscopy for Process Monitoring and Wide-Area Height Determination of Vertically-Aligned Carbon Nanotube Forests

“…Using chemical vapor deposition (CVD), nanotubes can be synthesized as ordered arrays of vertically aligned carbon nanotubes (VACNT) on a relatively large area [6][7][8]. Especially, the height of a VACNT forest is a crucial structural factor and determines performance in many applications.…”