Issue 7, 2015

A high-rate aqueous symmetric pseudocapacitor based on highly graphitized onion-like carbon/birnessite-type manganese oxide nanohybrids

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 (τ = 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.

Graphical abstract: A high-rate aqueous symmetric pseudocapacitor based on highly graphitized onion-like carbon/birnessite-type manganese oxide nanohybrids

Supplementary files

Article information

Article type
Paper
Submitted
07 Dec 2014
Accepted
15 Dec 2014
First published
15 Dec 2014
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2015,3, 3480-3490

Author version available

A high-rate aqueous symmetric pseudocapacitor based on highly graphitized onion-like carbon/birnessite-type manganese oxide nanohybrids

K. Makgopa, P. M. Ejikeme, C. J. Jafta, K. Raju, M. Zeiger, V. Presser and K. I. Ozoemena, J. Mater. Chem. A, 2015, 3, 3480 DOI: 10.1039/C4TA06715K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements