dc.contributor.author |
Makgopa, Katlego
|
|
dc.contributor.author |
Ejikeme, Paul Madus
|
|
dc.contributor.author |
Jafta, Charl Jeremy
|
|
dc.contributor.author |
Raju, Kumar
|
|
dc.contributor.author |
Zeiger, Marco
|
|
dc.contributor.author |
Presser, Volker
|
|
dc.contributor.author |
Ozoemena, Kenneth I.
|
|
dc.date.accessioned |
2015-03-24T09:58:18Z |
|
dc.date.available |
2015-03-24T09:58:18Z |
|
dc.date.issued |
2015-02 |
|
dc.description.abstract |
We present a study on the pseudocapacitive properties of birnessite-type MnO2 grafted on highly
graphitized onion-like carbon (OLC/MnO2). In a three-electrode setup, we evaluated two different
substrates, namely a platinum disc and nickel foam. The OLC/MnO2 nanohybrid exhibited a large specific
capacitance (Csp) of 295 and 323 F g 1 (at 1 A g 1) for the Pt disc and Ni foam, respectively. In addition,
the Ni foam substrate exhibited much higher rate capability (power density) than the Pt disc. A
symmetrical two-electrode device, fabricated with the Ni foam, showed a large Csp of 254 F g 1, a
specific energy density of 5.6 W h kg 1, and a high power density of 74.8 kW kg 1. These values have
been the highest for onion-based electrodes so far. The device showed excellent capacity retention
when subjected to voltage-holding (floating) experiments for 50 h. In addition, the device showed a very
short time constant (s ¼ 40 ms). This high rate handling ability of the OLC/MnO2 nanohybrid, compared
to literature reports, promises new opportunities for the development of aqueous-based pseudocapacitors. |
en_ZA |
dc.description.librarian |
hb2015 |
en_ZA |
dc.description.sponsorship |
CSIR. South Africa's Department of Science and Technology (DST) and National
Research Foundation (NRF) under the “Nanotechnology Flagship
Programme” (supercapacitors and fuel cell project, Grant no:
69849). |
en_ZA |
dc.description.uri |
http://www.rsc.org/MaterialsA |
en_ZA |
dc.identifier.citation |
Makgopa, K, Ejikeme, PM, Jafta, CJ, Raju, K, Zeiger, M, Presser, V & Ozoemena, KI 2015, 'A high-rate aqueous symmetric pseudocapacitor based on highly graphitized onion-like carbon/birnessite-type manganese oxide nanohybrids', Journal of Materials Chemistry A, vol. 3, no. 7, pp. 3480-3490. |
en_ZA |
dc.identifier.issn |
2050-7488 (print) |
|
dc.identifier.issn |
2050-7496 (online) |
|
dc.identifier.other |
10.1039/c4ta06715k |
|
dc.identifier.uri |
http://hdl.handle.net/2263/44136 |
|
dc.language.iso |
en |
en_ZA |
dc.publisher |
Royal Society of Chemistry |
en_ZA |
dc.rights |
© The Royal Society of Chemistry 2015. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
en_ZA |
dc.subject |
Birnessite-type manganese oxide nanohybrids |
en_ZA |
dc.subject |
Onion-like carbon (OLC) |
en_ZA |
dc.subject |
Electrical double-layer capacitors (EDLCs) |
en_ZA |
dc.subject |
Pseudocapacitors |
en_ZA |
dc.title |
A high-rate aqueous symmetric pseudocapacitor based on highly graphitized onion-like carbon/birnessite-type manganese oxide nanohybrids |
en_ZA |
dc.type |
Article |
en_ZA |