Electronic conduction mechanism in yttria-stabilized zirconia-titania under reducing atmospheres

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1837276· OSTI ID:428176

Swider, K E; Worrell, W L ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering

Yttria [12 mole percent (m/o)] stabilized zirconia with 5 to 10 m/o titania (YZTi) exhibits oxygen-ion and n-type conductivity under reducing atmospheres at elevated temperatures. Electron paramagnetic resonance (EPR) measurements reveal that the Ti{sup 3+} concentration of YZTi increases with increasing temperature, increasing TiO{sub 2} content, and decreasing oxygen pressures below 10{sup {minus}10} atm at 830 C. Impedance measurements show that the total electrical (oxygen-ion plus n-type) conductivity of YZTi having 10 m/o TiO{sub 2} follows the same behavior and increases at oxygen pressures below 10{sup {minus}15} atm at 838 C. The EPR and impedance results support an electron hopping mechanism between the 3{sup +} and 4{sup +} oxidation states of titanium. Modeling of the impedance data verifies that the n-type conductivity occurs in the YZTi lattice and is not restricted to the grain boundaries. A percolation model shows that electron hopping can occur in YZTi when titanium ions occupy as few as 3 to 4% of the cation sites.

• Sponsoring Organization: National Science Foundation, Washington, DC (United States); Gas Research Inst., Chicago, IL (United States)
• OSTI ID: 428176
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 11 Vol. 143; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
ANODES
CONCENTRATION RATIO
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRIC IMPEDANCE
MATHEMATICAL MODELS
SOLID ELECTROLYTE FUEL CELLS
TITANIUM OXIDES
YTTRIUM OXIDES
ZIRCONIUM OXIDES