Modifying the characteristics of carbon nanotubes grown on metallic substrates for ultracapacitor applications

Journal Article · Wed May 28 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4880197· OSTI ID:22304354

Kassakian, J. G. ^[1]; McCarthy, A. ^[2]

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1. Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2. Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

This paper reports the design, fabrication, and testing of carbon nanotube (CNT)-based ultracapacitor electrodes and provides quantitative results, showing that total electrode surface area—and, correspondingly, the total cell capacitance—is highly sensitive to the amount of catalyst material deposited prior to CNT growth. We deposit between 0.6 and 1.0 nm of iron catalyst on metallic (tungsten) substrates and synthesized vertically aligned CNT forests directly by thermal chemical vapor deposition. A capacitance maximum is observed with electrodes prepared with 0.8 nm of catalyst. Geometrical arguments based on average CNT diameter and areal density are used to corroborate this result. The CNTs' differential capacitance is found to be independent of their areal density, mean diameter, length, and the amount of catalyst used to grow them.

• OSTI ID: 22304354
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 20 Vol. 115; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CAPACITANCE
CARBON NANOTUBES
CATALYSTS
CHEMICAL VAPOR DEPOSITION
ELECTRODES
FABRICATION
SUBSTRATES
SURFACE AREA