Determination of oxygen nonstoichiometry and diffusivity in mixed conducting oxides by oxygen coulometric titration. 2: Oxygen nonstoichiometry and defect model for La{sub 0.8}Sr{sub 0.2}CoO{sub 3{minus}{delta}}
- Univ. of Twente, Enschede (Netherlands)
The oxygen nonstoichiometry of La{sub 0.8}Sr{sub 0.2}CoO{sub 3{minus}{delta}} has been determined as a function of oxygen partial pressure and temperature using a high-temperature coulometric titration cell. For each measured value of the oxygen chemical potential, the oxygen nonstoichiometry is found to be nearly independent of temperature. The equilibrium partial energy and entropy associated with oxygen incorporation have been determined as a function of oxygen nonstoichiometry and temperature. The results are interpreted in terms of a model in which it is assumed that conduction electrons, created during vacancy formation, gradually fill electron states in a wide electron band. A new relation between vacancy concentration, temperature, and oxygen partial pressure has been formulated which does not have the familiar appearance of a mass action type of equation.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 509382
- Journal Information:
- Journal of the Electrochemical Society, Vol. 144, Issue 4; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
Oxygen nonstoichiometry of La sub 1 minus x Sr sub x CoO sub 3 minus. delta. (0 < x le 0. 6)
High-temperature coulometric titration of La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}}: Evidence for the effect of electronic band structure on nonstoichiometry behavior