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Mixed Ionic and Electronic Conduction in Mn/Mo Doped Gadolinium Titanate

Published online by Cambridge University Press:  10 February 2011

J.J. Sprague
Affiliation:
Crystal Physics and Electroceramcs Laboratory, Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge MA, 02139, USA
H.L. Tuller
Affiliation:
Crystal Physics and Electroceramcs Laboratory, Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge MA, 02139, USA
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Abstract

Recent work has shown that Gd 2(Ti1−xMOx)2O7 (GT-Mo) exhibits high levels of mixed conduction under reducing atmospheres, making it suitable as an anode in a solid oxide fuel cell, but not as a cathode since it decomposes at high Po2. We have succeeded in extending the stability limits of GT-Mo to higher Po2 with the addition of Mn. Our earlier studies on Gd2((MoyMn1−y)xTi1−x)2O7 (GMMT) as a function of Po2,T, and composition utilizing impedance spectroscopy and x-ray diffraction are extended to include a wider range of compositions (x ≤ 0.3). In addition, a new sintering method for the GMMT material is introduced that compensates for observed materials loss and abnormal conduction behavior in previous studies. Defect models explaining the dependence of the conductivity on oxygen partial pressure, temperature, and composition are presented as well.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

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References

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