Diffusion-Controlled Creep in Mixed-Conducting Oxides

Determination of Oxygen Nonstoichiometry and Diffusivily in Mixed Conducting Oxides by Oxygen Coulometric Titration I. Chemical Diffusion in La085r02CoO3_5

Oxygen coulometric titration has been applied to measure chemical diffusion in La0 45r0 2CoO36 between 700 and 1000°C. The transient current response to a potentiostatic step has been transformed from the time domain to the frequency domain. The equivalent circuit used to fit the resulting impedance data contains the element that describes the finite-length diffusion of oxygen into the sample s...

Proton-conducting Oxides

■ Abstract The structural and chemical parameters determining the formation and mobility of protonic defects in oxides are discussed, and the paramount role of high-molar volume, coordination numbers, and symmetry are emphasized. Symmetry also relates to the structural and chemical matching of the acceptor dopant. Y-doped BaZrO 3-based oxides are demonstrated to combine high stability with high...

Diffusion in Oxides

Towards an Improved Understanding of Electrochemical Oxygen Exchange Reactions on Mixed Conducting Oxides

In solid oxide fuel cells or electrolysis cells with ionic and electronic conducting electrodes, the electrochemical reactions take place at the gas/solid interface of the mixed conducting electrode. This is in contrast to the situation met in aqueous electrolytes, where the reactions occur at the electrode/electrolyte interface. Thus, modified concepts are required to describe the reaction rat...

Oxygen surface exchange kinetics of SrTi(1-x)Fe(x)O(3-δ) mixed conducting oxides.

The oxygen surface exchange kinetics of mixed conducting perovskite oxides SrTi(1-x)Fe(x)O(3-δ) (x = 0, 0.01, 0.05, 0.35, 0.5) has been investigated as a function of temperature and oxygen partial pressure using the pulse-response (18)O-(16)O isotope exchange (PIE) technique. Arrhenius activation energies range from 140 kJ mol(-1) for x = 0 to 86 kJ mol(-1) for x = 0.5. Extrapolating the temper...