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Highly porous activated glassy carbon film sandwich structure for electrochemical energy storage in ultracapacitor applications: Study of the porous film structure and gradient

Published online by Cambridge University Press:  31 January 2011

Artur Braun ,
Soenke Seifert  and
Jan Ilavsky
Artur Braun*
Affiliation:
Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for High Performance Ceramics, CH-8600 Dübendorf, Switzerland; Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506; and General Energy Research Department, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
Jan Ilavsky
Affiliation:
Argonne National Laboratory, Advanced Photon Source, Argonne, Illinois 60439
*
a)Address all correspondence to this author. e-mail: artur.braun@alumni.ethz.ch
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Abstract

Glassy carbon plates were thermochemically gas phase oxidized to obtain monolithic sandwichlike electrode assemblies with high surface area porous films for electrochemical energy storage applications. Film thicknesses were varied by variation of oxidation parameters time, temperature, and oxygen concentration and measured with electron microscopy. The mass density of the porous carbon film material was estimated by fitting a geometrical model to experimental gravimetric data. Optical Raman spectroscopy line scans suggest that the porosity has a gradient between the surface and the film/bulk interface, which is supported by pore-size distribution data obtained from small-angle x-ray scattering (SAXS) on slightly oxidized and fully oxidized samples. Detailed inspection of the power law behavior of SAXS data suggests that the internal surface area of well-oxidized glassy carbon (GC) is compact and extends over the entire probed volume and thus has optimal pore connectivity. This effect goes along with pore enlargement and a relative decrease of internal surface area per volume. Slightly oxidized carbon has no pore space with a compact, high connectivity internal surface area. The corresponding SAXS power law and the x-ray density suggest that this high volumetric surface area must be interpreted as a result of surface roughness, rather than true geometric or volumetric surface area. In consequence, is this surface area of limited use for electrochemical energy storage?

Keywords

PorosityOxidationEnergy storage
Type
Articles
Information
Journal of Materials Research , Volume 25 , Issue 8: Materials for Electrical Energy Storage , August 2010 , pp. 1532 - 1540
Copyright
Copyright © Materials Research Society 2010

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References

REFERENCES

1.Lewis, J.C., Redfern, B., Cowlard, F.C.Vitreous carbon as a crucible material for semiconductors. Solid-State Electron. 6, (3)251 (1963)Google Scholar
2.Jenkins, G.M., Kawamura, K.Polymeric Carbons—Carbon Fiber, Glass and Char 1st ed (Cambridge University Press, Cambridge UK 1976)Google Scholar
3.Braun, A., Bärtsch, M., Schnyder, B., Kötz, R.A model for the film growth in samples with two moving boundaries—An application and extension of the unreacted-core model. Chem. Eng. Sci. 55, (22)5245 (2000)CrossRefGoogle Scholar
4.Braun, A., Wokaun, A., Hermanns, H-G.Analytical solution to a growth problem with two moving boundaries. Appl. Math. Model 27, (1)47 (2003)CrossRefGoogle Scholar
5.Lewis, J.C., Floyd, I.J., Cowlard, F.C.A comparative study of gaseous oxidation of vitreous carbon and various graphites at 1500–3000 degrees K. Carbon 6, (2)223 (1968)CrossRefGoogle Scholar
6.Miklos, J., Mund, K., Naschwitz, W. Patent DE 30 11 701 A1. Siemens AG and German Patent Office (1980)Google Scholar
7.Braun, A., Bärtsch, M., Schnyder, B., Kötz, R., Haas, O., Haubold, H-G., Goerigk, G.X-ray scattering and adsorption studies of thermally oxidized glassy carbon. J. Non-Cryst. Solids 260, (1–2)1 (1999)CrossRefGoogle Scholar
8.Braun, A., Bärtsch, M., Geiger, F., Haas, O., Kötz, R., Schnyder, B., Carlen, M., Christen, T., Ohler, C., Unternährer, P., Desilvestro, H., Krause, E.A study on oxidized glassy carbon sheets for bipolar supercapacitor electrodesNew Materials for Batteries and Fuel edited by D.H. Doughty, L.F. Nazar, M. Arakawa,H-P. Brack, and K. Naoi (Mater. Res. Soc. Symp. Proc 575, Warrendale, PA 1999)369Google Scholar
9.Braun, A., Bärtsch, M., Merlo, O., Schaffner, B., Schnyder, B., Kötz, R., Haas, O., Wokaun, A.Evolution of electrochemical double layer capacitance in glassy carbon during thermal oxidation—Crossover from exponential to logistic growth. Carbon 41, (4)759 (2003)Google Scholar
10.Braun, A., Bärtsch, M., Schnyder, B., Kötz, R., Haas, O., Wokaun, A.Evolution of BET internal surface area in glassy carbon powder during thermal oxidation. Carbon 40, (3)375 (2002)CrossRefGoogle Scholar
11.Bärtsch, M., Braun, A., Schnyder, B., Kötz, R., Haas, O.Bipolar glassy carbon electrochemical double-layer capacitor: 100,000 cycles demonstrated. J. New Mater. Electrochem. Syst. 2, 273 (1999)Google Scholar
12.Conway, B.E., Pell, W.G.Double-layer and pseudocapacitance types of electrochemical capacitors and their applications to the development of hybrid devices. J. Solid State Electrochem. 7, (9)637 (2003)CrossRefGoogle Scholar
13.Braun, A., Kohlbrecher, J., Bärtsch, M., Schnyder, B., Kötz, R., Haas, O., Wokaun, A.Small angle neutron scattering and cyclic voltammetry study on electrochemically oxidized and reduced pyrolytic carbon. Electrochim. Acta 49, (7)1105 (2004)Google Scholar
14.Rothwell, W.S.Small-angle x-ray scattering from glassy carbon. J. Appl. Phys. 39, (3)1840 (1968)CrossRefGoogle Scholar
15.Ilavsky, J., Jemian, P.R., Allen, A.J., Zhang, F., Levine, L.E., Long, G.G.Ultra-small-angle x-ray scattering at the advanced photon source. J. Appl. Crystallogr. 42, (3)469 (2009)CrossRefGoogle Scholar
16.Ilavsky, J., Jemian Irena, P.R.Tool suite for modeling and analysis of small-angle scattering. J. Appl. Crystallogr. 42, (2)347 (2009)CrossRefGoogle Scholar
17.Glatter, O., Kratky, O.Small Angle X-Ray Scattering (Academic Press, New York)Google Scholar
18.Spahr, M.E., Palladino, T., Wilhelm, H., Würsig, A., Goers, D., Buqa, H., Holzapfel, M., Novak, P.J Electrochem Soc. 151, (9)A1383 (2004)Google Scholar
19.Vogel, H.J.Morphological determination of pore connectivity as a function of pore size using serial sections. Eur. J. Soil Sci. 48, (3)365 (1997)Google Scholar
20.Wong, P., Bray, A.J.Scattering by rough surfaces. Phys. Rev. B 37, 7751 (1988)Google Scholar
21.Allen, A.J., Ilavsky, J., Braun, A.Multi-scale microstructure characterization of solid oxide fuel cell assemblies with ultra small-angle x-ray scattering. Adv. Eng. Mater. 11, (6)495 (2009)Google Scholar