Analysis of charge transfer for in situ li intercalated carbon nanotubes
Date
2012Source Title
Journal of Physical Chemistry C
Print ISSN
1932-7447
Electronic ISSN
1932-7455
Publisher
American Chemical Society
Volume
116
Issue
20
Pages
11364 - 11369
Language
English
Type
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Abstract
Vertically aligned carbon nanotube (VA-CNT)
arrays have been synthesized with lithium (Li) intercalation
through an alcohol-catalyzed chemical vapor deposition technique
by using a Li-containing catalyst. Scanning electron microscopy
images display that synthesized carbon nanotubes (CNTs) are
dense and vertically aligned. The effect of the Li-containing
catalyst on VA-CNTs has been studied by using Raman
spectroscopy, X-ray photoelectron spectroscopy (XPS), and
electron energy loss spectroscopy (EELS). XPS results show the
change in binding energy of Li 1s and C 1s peaks, which indicates
that Li is inserted in VA-CNTs during growth. Analysis of Raman
spectra reveals that the G-band profile of CNTs synthesized with the Li-containing catalyst is shifted, suggesting an electronic
interaction between Li and neighboring C atoms of the CNTs. The EELS spectra of the C K edge and Li K edge from CNTs also
confirmed that Li is inserted into CNTs during synthesis. We have performed ab inito calculations based on density functional
theory for a further understanding of the structural and electronic properties of Li intercalated CNTs, especially addressing the
controversial charge-transfer state between Li and C.