Abstract
Nickel oxides on carbon nanotube electrodes (NiOx/CNT electrodes) are prepared by depositing Ni(OH)2 electrochemically onto carbon nanotube (CNT) film substrates with subsequent heating to 300 °C. Compared with the as deposited Ni(OH)2 on CNT film substrates (Ni(OH)2/CNT electrodes), the 300 °C heat treated electrode shows much high rate capability, which makes it suitable as an electrode in supercapacitor applications. X-ray photoelectron spectroscopy shows that the pseudocapacitance of the NiOx/CNT electrodes in a 1 M KOH solution originates from redox reactions of NiOx/NiOxOH and Ni(OH)2/NiOOH. The 8.9 wt.% NiOx in the NiOx/CNT electrode shows a NiOx-normalized specific capacitance of 1701 F g-1 with excellent high rate capability due to the 3-dimensional nanoporous network structure with an extremely thin NiOx layer on the CNT film substrate. On the other hand, the 36.6 wt.% NiOx/CNT electrode has a maximum geometric and volumetric capacitance of 127 mF cm-2 and 254 F cc-1, respectively, with a specific capacitance of 671 F g-1, which is much lower than that of the 8.9% NiOx electrode. This decrease in specific capacitance of the high wt.% NiOx/CNT electrodes can be attributed to the dead volume of the oxides, high equivalent series resistance for a heavier deposit, and the ineffective ionic transportation caused by the destruction of the 3-dimensional network structure. Deconvolution analysis of the cyclic voltammograms reveals that the rate capability of the NiOx/CNT electrodes is adversely affected by the redox reaction of Ni(OH)2, while the adverse effects from the reaction of NiOx is insignificant.
| Original language | English |
|---|---|
| Pages (from-to) | 642-652 |
| Number of pages | 11 |
| Journal | Journal of Power Sources |
| Volume | 182 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2008 Aug 1 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering
Cite this
}
Pseudocapacitive properties of electrochemically prepared nickel oxides on 3-dimensional carbon nanotube film substrates. / Nam, Kyung Wan; Kim, Kwang Heon; Lee, Eun Sung; Yoon, Won Sub; Yang, Xiao Qing; Kim, Kwang Bum.
In: Journal of Power Sources, Vol. 182, No. 2, 01.08.2008, p. 642-652.Research output: Contribution to journal › Article
TY - JOUR
T1 - Pseudocapacitive properties of electrochemically prepared nickel oxides on 3-dimensional carbon nanotube film substrates
AU - Nam, Kyung Wan
AU - Kim, Kwang Heon
AU - Lee, Eun Sung
AU - Yoon, Won Sub
AU - Yang, Xiao Qing
AU - Kim, Kwang Bum
PY - 2008/8/1
Y1 - 2008/8/1
N2 - Nickel oxides on carbon nanotube electrodes (NiOx/CNT electrodes) are prepared by depositing Ni(OH)2 electrochemically onto carbon nanotube (CNT) film substrates with subsequent heating to 300 °C. Compared with the as deposited Ni(OH)2 on CNT film substrates (Ni(OH)2/CNT electrodes), the 300 °C heat treated electrode shows much high rate capability, which makes it suitable as an electrode in supercapacitor applications. X-ray photoelectron spectroscopy shows that the pseudocapacitance of the NiOx/CNT electrodes in a 1 M KOH solution originates from redox reactions of NiOx/NiOxOH and Ni(OH)2/NiOOH. The 8.9 wt.% NiOx in the NiOx/CNT electrode shows a NiOx-normalized specific capacitance of 1701 F g-1 with excellent high rate capability due to the 3-dimensional nanoporous network structure with an extremely thin NiOx layer on the CNT film substrate. On the other hand, the 36.6 wt.% NiOx/CNT electrode has a maximum geometric and volumetric capacitance of 127 mF cm-2 and 254 F cc-1, respectively, with a specific capacitance of 671 F g-1, which is much lower than that of the 8.9% NiOx electrode. This decrease in specific capacitance of the high wt.% NiOx/CNT electrodes can be attributed to the dead volume of the oxides, high equivalent series resistance for a heavier deposit, and the ineffective ionic transportation caused by the destruction of the 3-dimensional network structure. Deconvolution analysis of the cyclic voltammograms reveals that the rate capability of the NiOx/CNT electrodes is adversely affected by the redox reaction of Ni(OH)2, while the adverse effects from the reaction of NiOx is insignificant.
AB - Nickel oxides on carbon nanotube electrodes (NiOx/CNT electrodes) are prepared by depositing Ni(OH)2 electrochemically onto carbon nanotube (CNT) film substrates with subsequent heating to 300 °C. Compared with the as deposited Ni(OH)2 on CNT film substrates (Ni(OH)2/CNT electrodes), the 300 °C heat treated electrode shows much high rate capability, which makes it suitable as an electrode in supercapacitor applications. X-ray photoelectron spectroscopy shows that the pseudocapacitance of the NiOx/CNT electrodes in a 1 M KOH solution originates from redox reactions of NiOx/NiOxOH and Ni(OH)2/NiOOH. The 8.9 wt.% NiOx in the NiOx/CNT electrode shows a NiOx-normalized specific capacitance of 1701 F g-1 with excellent high rate capability due to the 3-dimensional nanoporous network structure with an extremely thin NiOx layer on the CNT film substrate. On the other hand, the 36.6 wt.% NiOx/CNT electrode has a maximum geometric and volumetric capacitance of 127 mF cm-2 and 254 F cc-1, respectively, with a specific capacitance of 671 F g-1, which is much lower than that of the 8.9% NiOx electrode. This decrease in specific capacitance of the high wt.% NiOx/CNT electrodes can be attributed to the dead volume of the oxides, high equivalent series resistance for a heavier deposit, and the ineffective ionic transportation caused by the destruction of the 3-dimensional network structure. Deconvolution analysis of the cyclic voltammograms reveals that the rate capability of the NiOx/CNT electrodes is adversely affected by the redox reaction of Ni(OH)2, while the adverse effects from the reaction of NiOx is insignificant.
UR - http://www.scopus.com/inward/record.url?scp=45449095183&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=45449095183&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2008.03.090
DO - 10.1016/j.jpowsour.2008.03.090
M3 - Article
AN - SCOPUS:45449095183
VL - 182
SP - 642
EP - 652
JO - Journal of Power Sources
JF - Journal of Power Sources
SN - 0378-7753
IS - 2
ER -