2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 10: Battery, Recycling, Environmental, Mining
| Editors: | Kongoli F, Kumar V, Aifantis K, Pagnanelli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 220 pages |
| ISBN: | 978-1-987820-54-6 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Unzipped carbon nanotubes via KOH activation for energy storage devices
Kwang Chul Roh1; Joah Han2;1KOREA INSTITUTE OF CERAMIC ENGINEERING AND TECHNOLOGY, Jinju-si, Korea (Republic of [South] Korea); 2KOREA INSTITUTE OF CERAMIC ENGINEERING OF TECHNOLOGY, Jinju-si, Korea (Republic of [South] Korea);
Type of Paper: Regular
Id Paper: 492
Topic: 14
Abstract:
CNTs have been widely studied for a various field such as hydrogen storage, field emission materials and electrode materials for energy storage devices due to physical and chemical properties. We suggest unzipped CNTs with high specific surface area (1123 m2 g-1) and total pore volume (2.38 cm3 g-1) and a trimodal (micro-meso-macro) pore structure through alkali activation for energy storage devices. After severe alkali activation (in our study, CNT (C)/KOH = 1:10 (w/w) at 1000 °C), various pores were initially formed on the surface. Subsequently, a longitudinally unzipped structure was obtained as the individual pores connected. In contrast with other methods to prepare unzipped and porous CNTs, this method is economical and scalable because it enables a one-step synthesis of unzipped and porous CNTs. As per the non-localized density functional theory (NL-DFT), the distribution of micro-meso pores showed evidence of unzipping because the peak for pore sizes <1 nm, measured from the partially opened tips of the pristine CNTs, was broadened. Since the tips were perfectly opened after activation, this means that the micropores on the unzipped structure increased. In addition, the results showed that the unzipped porous CNTs had a trimodal pore structure. This structure resulted in increased specific surface area, as well as energy storage and adsorption capacities. Thus, we applied the unzipped CNTs for energy storage devices including lithium-sulfur (Li-S) secondary batteris and ultracapacitors. At the results, initial specific capacity is obtained over 950 mA g-1 (50% of theoretical specific capacity) in Li-S secondary batteries and the maximum energy density of the unzipped porous CNTs in ultracapacitors based on an organic electrolyte was 50 W h kg-1. Thus, the method is suitable for fabrication of unzipped porous CNTs, which show potential as energy efficient materials.