Graphene oxide nanoribbons and their applications in supercapacitors

Document Type: Research Paper

Authors

Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

We report the enhanced capacitance of the Multi-Walled Carbon NanoTubes (MWCNTs) after a chemical unzipping process in concentrated sulfuric acid (H2SO4) and potassium permanganate (KMnO4). The effects of the test duration and temperature were investigated on the unzipping process of the MWCNTs to synthesize the graphene oxide nanoribbons. The SEM and TEM studies were carried out on untreated and unzipped MWCNTs samples to investigate the cutting and unzipping of the MWCNTs. The results confirmed that the efficient tube unzipping with improved effective surface area was obtained from the 1h treatment at 60°C, at which most of the tubes were opened without any tube annihilation. The graphite plate deposited with the untreated and unzipped MWCNTs samples was investigated by electrochemical studies. Cyclic voltammetry studies showed that the MWCNTs after 1h unzipping at 60°C had better electrochemical behavior than the other samples. Galvanostatic charging/discharging measurements were carried out on the untreated and unzipped MWCNTs samples. A remarkable specific capacitance of 33 Fg-1 was obtained for the unzipped MWCNTs at a current density of 1 Ag-1 in 0.5 M KCl solution compared with 8 Fg-1 for pristine MWCNTs, again confirming the enhanced effective surface area and increased defect density in the tube surfaces after the unzipping process. These results make the unzipped MWCNTs a promising electrode material for all energy storage applications.

Keywords


[1].Bohlen,O., Kowal,J., Sauer,D.U., J. Power Sources Vol. 172 (2007) pp. 468-75.
[2].Lewandowski,A., Galinski,M., J. Power Sources Vol. 173 (2007) pp. 822-28.
[3].Winter,M., Brodd,R.J., J. Chem. Rev. Vol. 104 (2004) pp. 4245-69.
[4].Pandolfo,A.G., Hollenkamp,A.F., J. Power Sources Vol. 157 (2006) pp. 11-27.
[5].Lokhande,C.D., Dubal,D.P., Joo,O.-S., J. Current Applied Physics Vol. 11 (2011) pp. 255-70.
[6].Zhang,Y., Feng,H., Wu,X., Wang,L., Zhang,A., Xia,T., Dong,H., Li,X., Zhang,L.,Int. J. Hydrogen Energy Vol.34 (2009) pp. 4889-99.
[7].Inagaki,M., Konno,H., Tanaike,O., J. Power Sources Vol. 195 (2010) pp. 7880-7903.
[8].Wang,G., Ling,Y., Qian,F., Yang,X., Liu,X.-X., Li,Y., J. Power Sources Vol. 196 (2011) pp. 5209-14.
[9]. Zhang,H., Cao,G., Yang,Y., Gu,Z.,J. Electrochem. Soc. Vol. 155 (2008) pp. K19-K22.
[10]. E. Frackowiak, S. Delpeux, K. Jurewicz, K. Szostak, D. Cazorla-Amoros, F. Beguin, 

Enhanced capacitance of carbon nanotubes through chemical activation, Chem. Phys. Lett. Vol. 361 (2002) pp. 35-41.
[11]. Y.-M. Dai, W.-J. Liu, T.-C. Pan, J.-M. Jehng, Surface activation on multi-wall carbon nanotube for electrochemical capacitor applications, Appl. Surf. Sci. Vol. 258 (2012) pp. 3027-3032.
[12]. K. Jurewicz, K. Babeł, R. Pietrzak, S. Delpeux, H. Wachowska, Capacitanceproperties of multi-walled carbon nanotubes modified by activation and ammoxidation, CarbonVol. 44 (2006) pp. 2368-2375.
[13]. C.-C. Hu, J.-H. Su, T.-C. Wen, Modification of multi-walled carbon nanotubes for electric double-layer capacitors: tube opening and surface functionalization, J. Phys. Chem.SolidsVol. 68 (2007) pp. 2353-2362.
[14]. C.G. Liu, H.T. Fang, F. Li, M. Liu, H.M. Cheng, Single-walled carbon nanotubesmodified by electrochemical treatment for application in electrochemical capacitors, J. Power SourcesVol. 160 (2006) pp. 758-761.