Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-25T16:47:53.175Z Has data issue: false hasContentIssue false

Mixed Ionic-Electronic Conduction in N1 Doped Lanthanum Gallate Perovskites

Published online by Cambridge University Press:  10 February 2011

N. J. Long
Affiliation:
Industrial Research Limited Gracefield Rd, PO Box 31–310
H. L. Tuller
Affiliation:
Crystal Physics and Electroceramics Laboratory Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA 02139, U.S.A.
Lower Hurt
Affiliation:
Crystal Physics and Electroceramics Laboratory Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA 02139, U.S.A.
New Zealand
Affiliation:
Crystal Physics and Electroceramics Laboratory Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA 02139, U.S.A.
Get access

Abstract

Lanthanum gallate is a promising material for “monolithic” fuel cells or oxygen pumps, i.e. one in which the electrolyte and electrodes are formed from a common phase. We have investigated La1−xSrxGa1–yNiyO3 (LSGNx-y) with x=0.1 and y=0.2 and 0.5 as a potential cathode material for such an electrochemical device. The σ(PO2,T) for LSGN10–20 points to a p-type electronic conductivity at high PO2 and predominantly ionic conductivity at low PO2. LSGN10–50 has an electronic conductivity suitable for SOFC applications of approximately 50 S/cm in air at high temperature. AC impedance spectroscopy on an electron blocking cell of the form M/LSG/LSGN/LSG/M was used to isolate the ionic conductivity in the LSGN10–20 material. The ionic conductivity was found to have a similar magnitude and activation energy to that of undoped LSG material with σi= 0.12 S/cm at 800°C and EA= 1.0 ± 0.1 eV. Thermal expansion measurements on the LSGN materials were characterized as a function of temperature and dopant level and were found to match that of the electrolyte under opeating conditions.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Spears, M. and Tuller, H.L., in Solid State Ionics III, Nazri, G.A., Tarascon, J.M. and Armand, M., Editors, The Materials Research Society, Pittsburgh, PA, 1993, p. 301.Google Scholar
2. Porat, O., Spears, M.A., Heremans, C., Kosacki, I. and Tuller, H.L., Solid State Ionic 86–88, 285 (1996).Google Scholar
3. Liou, S. S. and Worrel, W.L., Appl. Phys. A, 49, 25 (1989).Google Scholar
4. Ishihara, T., Matsuda, H., and Takita, Y., J. Amer. Chem. Soc., 116, 38013803 (1994).Google Scholar
5. Feng, M. and Goodenough, J.B., Eur. J. Solid State Chem. 31, 663672 (1994).Google Scholar
6. Kroger, F.A., in The Chemistry of Imperfect Crystals. North Holland, Amsterdam, 1974, p. 14.Google Scholar
7. Cox, P. A., in Transition Metal Oxides: An Introduction to their Electronic Structure and Properties, (Oxford University Press, 1992), p.220 Google Scholar
8. Long, N.J., Porat, O. and Tuller, H.L., in Proc. Third Int. Symp. on Ionic and Mixed Conducting Ceramics, The Electrochemical Soc., Paris, 1997, in press.Google Scholar
9. Riess, I., in Second Int. Symp. on Ionic and Mixed Conducting Ceramics, Ramanarayanan, T.A., Worrell, W.L. and Tuller, H.L., Editors, The Electrochemical Society, Pennington, NJ (1994) p. 286.Google Scholar
10. Ishihara, T., Matsuda, H., and Takita, Y., Solid State Ionics 79, 147151 (1995).Google Scholar
11. Ishihara, T., Kilner, J. A., Honda, M., and Takita, Y. J. Amer. Ceram. Soc. 119, 27472748 (1997).Google Scholar
12. Long, N.J. unpublished results.Google Scholar
13. Macdonald, J.R., J. Chem. Phys. 61, 3977 (1974).Google Scholar
14. Maier, J., Z. Phys. Chem. (NF) 140, 191 (1984).Google Scholar
15. Huang, P. and Petric, A., J. Electrochem. Soc, 143, 5, 16441648 (1996).Google Scholar
16. Opila, E.J. and Tuller, H.L., J. Amer. Ceram. Soc. 77, 2727–37 (1994).Google Scholar