Abstract

Herringbone graphite nanofibers (GNF) provide an interesting candidate for carbon exfoliation, with their slit-pore geometry, nano-scale dimensions, high aspect ratio, and graphitic layers that terminate along the fiber axis. Well-established graphite exfoliation techniques of acid intercalation followed by thermal treatment were applied to herringbone GNF, and the resulting fibers were characterized by HRTEM, XRD, EELS, EDS, TPO, gas adsorption, and cyclic voltammetry. Variations in thermal treatment led to drastic variations in the resulting fiber structure: A mild thermal treatment led to dislocations within the graphitic lattice and a 5% lattice expansion, whereas an extended thermal treatment led to an estimated 20-fold expansion and a ten-fold increase in surface area. The latter fiber had a unique structure with repeating interior amorphous carbon mesopores sandwiched between graphitic regions from the original herringbone morphology. The increased surface area of the exfoliated GNF correlated with increased low temperature hydrogen physisorption, whereas the observed dislocations in the graphitic structure correlated with ambient temperature hydrogen adsorption. Mild oxidation of the exfoliated GNF allowed access to the interior mesopores and led to an increased electrical double layer capacitance. These results suggest that selective exfoliation of a nanocarbon is a means to induce interior mesorpores with a controlled pore size distribution which in turn will control the relative adsorption binding energy and the accessibility of mesopores for electrical double layer capacitors. Work to control the interior pore size to provide optimal lattice spacing for a given application will be discussed.

Original languageEnglish (US)
Number of pages1
StatePublished - Jan 1 2005
Event05AIChE: 2005 AIChE Annual Meeting and Fall Showcase - Cincinnati, OH, United States
Duration: Oct 30 2005Nov 4 2005

Other

Other05AIChE: 2005 AIChE Annual Meeting and Fall Showcase
CountryUnited States
CityCincinnati, OH
Period10/30/0511/4/05

Fingerprint

Nanofibers
Graphite
Capacitance
Adsorption
Heat treatment
Fibers
Pore size
Hydrogen
Gas adsorption
Physisorption
Electron energy loss spectroscopy
Amorphous carbon
Intercalation
Binding energy
Cyclic voltammetry
Aspect ratio
Energy dispersive spectroscopy
Capacitors
Oxidation
Temperature

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Lueking, A., Rajagopalan, R., Pan, L., Clifford, C. E., & Narayanan, D. (2005). Exfoliated graphite nanofibers: Structure, adsorption, and electric double-layer capacitance. Paper presented at 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States.
Lueking, Angela ; Rajagopalan, Ramakrishnan ; Pan, Ling ; Clifford, Caroline Elaine ; Narayanan, Deepa. / Exfoliated graphite nanofibers : Structure, adsorption, and electric double-layer capacitance. Paper presented at 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States.1 p.
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abstract = "Herringbone graphite nanofibers (GNF) provide an interesting candidate for carbon exfoliation, with their slit-pore geometry, nano-scale dimensions, high aspect ratio, and graphitic layers that terminate along the fiber axis. Well-established graphite exfoliation techniques of acid intercalation followed by thermal treatment were applied to herringbone GNF, and the resulting fibers were characterized by HRTEM, XRD, EELS, EDS, TPO, gas adsorption, and cyclic voltammetry. Variations in thermal treatment led to drastic variations in the resulting fiber structure: A mild thermal treatment led to dislocations within the graphitic lattice and a 5{\%} lattice expansion, whereas an extended thermal treatment led to an estimated 20-fold expansion and a ten-fold increase in surface area. The latter fiber had a unique structure with repeating interior amorphous carbon mesopores sandwiched between graphitic regions from the original herringbone morphology. The increased surface area of the exfoliated GNF correlated with increased low temperature hydrogen physisorption, whereas the observed dislocations in the graphitic structure correlated with ambient temperature hydrogen adsorption. Mild oxidation of the exfoliated GNF allowed access to the interior mesopores and led to an increased electrical double layer capacitance. These results suggest that selective exfoliation of a nanocarbon is a means to induce interior mesorpores with a controlled pore size distribution which in turn will control the relative adsorption binding energy and the accessibility of mesopores for electrical double layer capacitors. Work to control the interior pore size to provide optimal lattice spacing for a given application will be discussed.",
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Lueking, A, Rajagopalan, R, Pan, L, Clifford, CE & Narayanan, D 2005, 'Exfoliated graphite nanofibers: Structure, adsorption, and electric double-layer capacitance' Paper presented at 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States, 10/30/05 - 11/4/05, .

Exfoliated graphite nanofibers : Structure, adsorption, and electric double-layer capacitance. / Lueking, Angela; Rajagopalan, Ramakrishnan; Pan, Ling; Clifford, Caroline Elaine; Narayanan, Deepa.

2005. Paper presented at 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States.

Research output: Contribution to conferencePaper

TY - CONF

T1 - Exfoliated graphite nanofibers

T2 - Structure, adsorption, and electric double-layer capacitance

AU - Lueking, Angela

AU - Rajagopalan, Ramakrishnan

AU - Pan, Ling

AU - Clifford, Caroline Elaine

AU - Narayanan, Deepa

PY - 2005/1/1

Y1 - 2005/1/1

N2 - Herringbone graphite nanofibers (GNF) provide an interesting candidate for carbon exfoliation, with their slit-pore geometry, nano-scale dimensions, high aspect ratio, and graphitic layers that terminate along the fiber axis. Well-established graphite exfoliation techniques of acid intercalation followed by thermal treatment were applied to herringbone GNF, and the resulting fibers were characterized by HRTEM, XRD, EELS, EDS, TPO, gas adsorption, and cyclic voltammetry. Variations in thermal treatment led to drastic variations in the resulting fiber structure: A mild thermal treatment led to dislocations within the graphitic lattice and a 5% lattice expansion, whereas an extended thermal treatment led to an estimated 20-fold expansion and a ten-fold increase in surface area. The latter fiber had a unique structure with repeating interior amorphous carbon mesopores sandwiched between graphitic regions from the original herringbone morphology. The increased surface area of the exfoliated GNF correlated with increased low temperature hydrogen physisorption, whereas the observed dislocations in the graphitic structure correlated with ambient temperature hydrogen adsorption. Mild oxidation of the exfoliated GNF allowed access to the interior mesopores and led to an increased electrical double layer capacitance. These results suggest that selective exfoliation of a nanocarbon is a means to induce interior mesorpores with a controlled pore size distribution which in turn will control the relative adsorption binding energy and the accessibility of mesopores for electrical double layer capacitors. Work to control the interior pore size to provide optimal lattice spacing for a given application will be discussed.

AB - Herringbone graphite nanofibers (GNF) provide an interesting candidate for carbon exfoliation, with their slit-pore geometry, nano-scale dimensions, high aspect ratio, and graphitic layers that terminate along the fiber axis. Well-established graphite exfoliation techniques of acid intercalation followed by thermal treatment were applied to herringbone GNF, and the resulting fibers were characterized by HRTEM, XRD, EELS, EDS, TPO, gas adsorption, and cyclic voltammetry. Variations in thermal treatment led to drastic variations in the resulting fiber structure: A mild thermal treatment led to dislocations within the graphitic lattice and a 5% lattice expansion, whereas an extended thermal treatment led to an estimated 20-fold expansion and a ten-fold increase in surface area. The latter fiber had a unique structure with repeating interior amorphous carbon mesopores sandwiched between graphitic regions from the original herringbone morphology. The increased surface area of the exfoliated GNF correlated with increased low temperature hydrogen physisorption, whereas the observed dislocations in the graphitic structure correlated with ambient temperature hydrogen adsorption. Mild oxidation of the exfoliated GNF allowed access to the interior mesopores and led to an increased electrical double layer capacitance. These results suggest that selective exfoliation of a nanocarbon is a means to induce interior mesorpores with a controlled pore size distribution which in turn will control the relative adsorption binding energy and the accessibility of mesopores for electrical double layer capacitors. Work to control the interior pore size to provide optimal lattice spacing for a given application will be discussed.

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M3 - Paper

ER -

Lueking A, Rajagopalan R, Pan L, Clifford CE, Narayanan D. Exfoliated graphite nanofibers: Structure, adsorption, and electric double-layer capacitance. 2005. Paper presented at 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States.