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Título

Single-walled carbon nanotubes as electrodes in supercapacitors

AutorPicó, Fernando; Rojo, J. M. ; Sanjuán, M. L.; Ansón Casaos, Alejandro ; Benito, Ana M. ; Callejas, M. Alicia; Maser, Wolfgang K. ; Martínez Fernández de Landa, María Teresa
Palabras claveCarbon nanotubes
Supercapacitors
Nanotube devices
Electrochemical electrodes
Adsorption
Oxidation
Heat treatment
Electrolytes
Raman spectra
Fecha de publicación30-abr-2004
EditorElectrochemical Society
CitaciónJournal of the electrochemical society 151(6): A831-A837 (2004)
ResumenAs-grown and modified single-walled carbon nanotubes (SWCNTs) have been used as electrochemical active materials of electrode for electrochemical capacitors (supercapacitors). A series of modified SWCNTs has been obtained by oxidation of the as-grown SWCNTs in air at increasing temperatures in the range 300-550°C. The as-grown and modified samples have been characterized by Raman spectroscopy, N2 adsorption, and transmission electron microscopy (TEM). Raman spectra of the modified samples show that heating at increasing temperature produces a decrease in the intensity of radial and tangential breathing modes of SWCNTs and an alteration of the structure of SWCNTs up to complete destruction at 550°C. Heat-treatment at 350°C leads to the highest specific surface area (644 m2 g–1) and the highest micropore volume (0.288 cm3 g–1). TEM images of the as-grown and 350°C-oxidized samples show a multicomponent structure with bundles of SWCNTs that are thinner in the oxidized sample compared to the as-grown one. The as-grown and 350°C-oxidized SWCNTs were mixed with polyvinylidenefluoride and compacted to get electrodes. 6 M KOH and 2 M H2SO4 aqueous solutions were utilized as electrolytes. The specific capacitances (30-140 F g–1) are discussed on the basis of the electrode material and the electrolyte chosen. The specific capacitance is higher for the 350°C-oxidized SWCNTs and when KOH is used as electrolyte. Typical values of the equivalent series resistance (ESR) are in the range 1-5 , except for the oxidized sample when KOH is used as electrolyte; in this case, ESR is higher. The thermal treatment improves the energy density but does not affect the power density, this last being higher when H2SO4 is used.
Descripción7 pages.-- PACS: 82.47.Uv; 82.45.Fk; 85.35.Kt; 68.43.Mn; 82.45.Yz; 82.45.Gj; 81.40.Gh; 78.30.Na
Versión del editorhttp://dx.doi.org/10.1149/1.1738678
URIhttp://hdl.handle.net/10261/21409
DOI10.1149/1.1738678
ISSN0013-4651
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