Long-term degradation of Ta2O5-doped Bi2O3 systems

Delta-phase bismuth oxide is a well-known high oxygen ion conductor and can be used as an electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). 5-10 mol% Ta2O5 was doped into Bi2O3 to stabilise the delta phase by solid state reaction. One Bi2O3 sample (7.5TSB) was stabilised by...

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Bibliographic Details
Published inJournal of the European Ceramic Society Vol. 31; no. 16; pp. 3081 - 3086
Main Authors Lin, S E, Wei, W C J
Format Journal Article
LanguageEnglish
Published 01.12.2011
Subjects
Bismuth oxides
Ceramics
Conductors (devices)
Degradation
Delta phase (crystals)
Electrolytes
Solid oxide fuel cells
Tantalum oxides
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Summary:Delta-phase bismuth oxide is a well-known high oxygen ion conductor and can be used as an electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). 5-10 mol% Ta2O5 was doped into Bi2O3 to stabilise the delta phase by solid state reaction. One Bi2O3 sample (7.5TSB) was stabilised by 7.5 mol% Ta2O5 and exhibited single phase delta-Bi2O3-like (type I) phase. Thermomechanical analysis, XRD, AC impedance and HRTEM were used to characterise the properties. The results showed that holding at 800-850 C for 1 h was the appropriate sintering condition to obtain dense samples. Evident conductivity degradation was found with 1000 h long-term treatment at 650 C due to the formation of the alpha-Bi2O3 phase and Bi3TaO7, and vacancy ordering in the Bi3TaO7 structure.
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ISSN:0955-2219
DOI:10.1016/j.jeurceramsoc.2011.04.015