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Raman scattering study of the staging kinetics in the c-face skin of pyrolytic graphite-H2SO4

Published online by Cambridge University Press:  31 January 2011

P.C. Eklund
Affiliation:
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506
C.H. Olk
Affiliation:
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506
F.J. Holler
Affiliation:
Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506
J.G. Spolar
Affiliation:
Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
E.T. Arakawa
Affiliation:
Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
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Abstract

Raman scattering from the ∼ 1600 cm−1 graphitic phonons is used to study the stage evolution of graphite-H2SO4 in the first ∼ 1000 Å of the bulk during electrochemical intercalation. The Raman results are compared to staging kinetics in the deep bulk studied previously by 00/ x-ray diffraction. For low cell currents, which establish quasiequilibrium conditions, the c-face surface of the highly oriented pyrolytic graphite (HOPG) in contact with the reactant rapidly changes stage index to n − 1 just as the bulk completes stage n. We conclude that the intercalant must cross the c-face plate boundary of the HOPG, probably entering at either grain boundaries, microcracks, or steps in the plate surface. During stage transitions, the Raman lines are observed to remain Lorentzian in shape, with constant width, indicating that an ordered stage n − 1 compound grows at the expense of an ordered stage n compound. In studies of partially submerged HOPG plates, the surface above the acid level is found to stage last, although the plate surface just below the acid level stages first. Lateral diffusion of the sulfate anions from regions below, to regions above the acid level, is apparently impeded for reasons that are not understood. During portions of the electrochemical reaction requiring only hydrogen rearrangement in the intercalate layers (“overcharging”), Raman spectra taken from above and below the acid level are observed to evolve in concert, indicating the protons are not similarly impeded.

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Articles
Copyright
Copyright © Materials Research Society 1986

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References

1The stage index n refers to the number of carbon (C) layers located between successive intercalate (I) layers (e.g., a stage 3 compound has the periodic stacking sequence ...ICCCICCC... . For recent reviews of graphite intercalation compounds see Dresselhaus, M. S. and Dresselhaus, G., Adv. Phys. 30, 139 (1981); and S. A. Solin, Adv. Chem. Phys. 49, 455 (1982).Google Scholar
2Bessenhard, J. O., Wudy, E., Moewald, H., Nickl, J. J., Biberacher, W., and Foag, W., Synth. Met. 7, 185 (1983).Google Scholar
3Metrot, A. and Fischer, J. E., Synth. Met. 3, 201 (1981).Google Scholar
4Dresselhaus, M. S. and Dresselhaus, G., in Topics in Applied Physics, edited by Cardona, M. and Guntherodt, G. (Springer, Berlin, 1982), Vol. 51, Chap. 2.Google Scholar
5A preliminary account of this work has been previously published: Oik, C. H., Yeh, V., Holler, F. J., and Eklund, P. C., in Materials Research Society Proceedings, edited by Dresselhaus, M. S., Dres-selhaus, G., Fischer, J. E., and Moran, M. J. (Elsevier, New York, 1983), Vol. 20, p. 259.Google Scholar
6Moore, A. W., in Chemistry and Physics of Carbon, edited by Walker, P. L. and Thrower, P. A. (Dekker, New York, 1973), Vol. 11, p. 69.Google Scholar
7Hooley, J. G., Mat. Sci. Eng. 31, 17 (1977).CrossRefGoogle Scholar
8Schaufhautl, P., J. Prakt. Chem. 21, 155 (1841).Google Scholar
9Aronson, S., Frishberg, C., and Frankl, G., Carbon 9, 715 (1971).CrossRefGoogle Scholar
10Aronson, S., LeMont, S., and Weiner, J., Inorg. Chem. 10, 1296 (1971).Google Scholar
11Rudorf, W., Adv. Inorg. Chem. Nucl. Chem. 1, 223 (1959).Google Scholar
12Giergiel, J., Ph.D. thesis, University of Kentucky, 1982.Google Scholar
13Reference 2 and references cited therein.Google Scholar
14Bottonley, M. J., Parry, G. S., Ubbelohde, A. R., and Young, D., J. Chem. Soc. 1963, 5674.Google Scholar
15Salaneck, W. R., Brucker, C. F., Fischer, J. E., and Metrot, A., Phys. Rev. B 24, 5037 (1981); see also the comments in Phys. Rev. B 28 (1982): L. B. Ebert and E. Appelman, p. 1637, and the reply by W. R. Salenck, C. F . Brucker, J. E. Fischer, and A. Metrot, p. 1639.Google Scholar
16Fujii, R. and Matsuo, K., Tanso 73, 44 (1973).Google Scholar
17MacRae, E., Metrot, A., Willman, P., and Herold, A., Physica B 99, 541 (1980).Google Scholar
18Metrot, A., Willmann, P., McRae, E., and Herold, A., Carbon 17, 182 (1979).CrossRefGoogle Scholar
19Eklund, P. C., Arakawa, E. T., Zarestky, J. L., Kamitakahara, W. A., and Mahan, G. D., Synth. Met. 12, 97 (1985).CrossRefGoogle Scholar
20Zabel, H. and Misenheimer, M. E., Phys. Rev. B 24, 1443 (1983).Google Scholar
21Nishitani, R., Uno, Y., and Suematsu, H., Phys. Rev. B 27, 6572 (1983).Google Scholar
22Kamitakahara, W. A., Eklund, P. C., and Zarestky, J. L. (private communication).Google Scholar
23Eklund, P. C., Spolar, J. G., Mahan, G. D. and Arakawa, E. T., Hoffman, D. M., and Zhang, J. M., Solid State Commun. 57(8), 567 (1986).Google Scholar
24Oik, C. H. and Eklund, P. C. (private communication).Google Scholar