Issue 10, 2013
From the journal:

Journal of Materials Chemistry A

Improved supercapacitor performance of MnO2–graphene composites constructed using a supercritical fluid and wrapped with an ionic liquid†

Ming-Tsung Lee,a   Chen-Yen Fan,a   Yi-Chen Wang,a   Hui-Ying Li,a   Jeng-Kuei Chang*abc  and  Chuan-Ming Tsengd  

* Corresponding authors

a Institute of Materials Science and Engineering, National Central University, 300 Jhongda Road, Taoyuan, Taiwan
E-mail: jkchang@ncu.edu.tw
Fax: +886-3-2805034
Tel: +886-3-4227151 ext. 34908

b Department of Chemical and Materials Engineering, National Central University, Taoyuan, Taiwan

c Department of Mechanical Engineering, National Central University, Taoyuan, Taiwan

d Institute of Physics, Academia Sinica, Taipei, Taiwan

Abstract

Supercritical CO2 (SCCO2) is used to synthesize MnO2. This process is found to be promising for producing oxide nanorods (∼5 nm in diameter) with little agglomeration. With suitable SCCO2 pressure and temperature, nanocrystalline α-MnO2 with an extremely high surface area of 245 m2 g−1 (versus 80 m2 g−1 for the oxide prepared in ambient air) was obtained. Introduction of graphene nanosheets and carbon nanotubes into MnO2 with and without the aid of SCCO2 is compared. SCCO2 can help debundle the graphene nanosheets and uniformly disperse the MnO2 nanorods in between, thus preventing graphene restacking. Since the oxide particles are sandwiched between the highly conductive sheets, a high electrochemical utilization is obtained. Accordingly, SCCO2-MnO2/graphene shows superior supercapacitor properties. The feasibility of using an ionic liquid (IL) as a conductive wrapping agent to improve the performance of the MnO2/graphene electrode is demonstrated. Because the intimate contact between the oxide and graphene can be ensured and the interfacial double-layer capacitance can be optimized, the electrode wrapped with an IL shows a higher capacitance, improved high-rate capability, and higher cyclic stability compared to those obtained without IL wrapping.

Graphical abstract: Improved supercapacitor performance of MnO2–graphene composites constructed using a supercritical fluid and wrapped with an ionic liquid

About
Cited by
Related
Download options Please wait...

Supplementary files

Article information

DOI
https://doi.org/10.1039/C2TA00986B
Article type
Paper
Submitted
05 Nov 2012
Accepted
02 Jan 2013
First published
29 Jan 2013

J. Mater. Chem. A, 2013,1, 3395-3405

Permissions

Request permissions

Improved supercapacitor performance of MnO2–graphene composites constructed using a supercritical fluid and wrapped with an ionic liquid

M. Lee, C. Fan, Y. Wang, H. Li, J. Chang and C. Tseng, J. Mater. Chem. A, 2013, 1, 3395 DOI: 10.1039/C2TA00986B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements