Surface Exchange and Bulk Diffusivity of LSCF as SOFC Cathode: Electrical Conductivity Relaxation and Isotope Exchange Characterizations

2013 ◽  
Vol 160 (4) ◽  
pp. F343-F350 ◽  
Author(s):  
Yihong Li ◽  
Kirk Gerdes ◽  
Teruhisa Horita ◽  
Xingbo Liu
Keyword(s):  
Electrical Conductivity ◽  
Isotope Exchange ◽  
Conductivity Relaxation ◽  
Sofc Cathode ◽  
Surface Exchange ◽  
Electrical Conductivity Relaxation ◽  
Bulk Diffusivity

Electrical Conductivity Relaxation Study of Solid Oxide Fuel Cell Cathodes using Epitaxial (001)-Oriented Strontium-Doped Lanthanum Manganite Thin Films

2010 ◽  
Vol 1255 ◽  
Author(s):  
Lu Yan ◽  
Balasubramaniam Kavaipatti ◽  
Shanling Wang ◽  
Hui Du ◽  
Paul Salvador
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Elevated Temperatures ◽  
Reduction Process ◽  
Lanthanum Manganite ◽  
Conductivity Relaxation ◽  
Surface Exchange ◽  
Electrical Conductivity Relaxation ◽  
Crystal Films ◽  
Surface Exchange Coefficient

AbstractEpitaxial single-crystal films of La0.7Sr0.3MnO3 (100) having smooth surface morphology were deposited on SrTiO3 (100) substrates by pulsed laser deposition (PLD). Electrical conductivity relaxation (ECR) measurements were carried out at elevated temperatures over a range of absolute oxygen pressures to determine the oxygen surface exchange coefficient. Steady-state conductivity data of the thin films show good agreement with the bulk material's properties. The values of the oxygen exchange coefficients (Kchem) are found to be similar for both oxidation and reduction process between 50 and 500 mTorr O2. The activation energy (Ea) of Kchem is 1.00±0.27 eV at temperatures above 600 °C and Kchem (T=612°C)≈1.2×10-6 cm/s.

scholarly journals Untangling surface oxygen exchange effects in YBa2Cu3O6+x thin films by electrical conductivity relaxation

2017 ◽  
Vol 19 (21) ◽  
pp. 14129-14140 ◽  
Author(s):  
P. Cayado ◽  
C. F. Sánchez-Valdés ◽  
A. Stangl ◽  
M. Coll ◽  
P. Roura ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Exchange Process ◽  
Bulk Diffusion ◽  
Epitaxial Thin Films ◽  
Conductivity Relaxation ◽  
Surface Exchange ◽  
Electrical Conductivity Relaxation ◽  
Relaxation Measurements ◽  
Kinetics Of

The kinetics of oxygen incorporation and excorporation in YBCO epitaxial thin films was investigated by electrical conductivity relaxation measurements showing that the oxygenation kinetics of YBCO films is limited by the surface exchange process of oxygen molecules prior to bulk diffusion into the films.

A Study of the Oxygen Transport Kinetics in SrFeO3-x

2002 ◽  
Vol 756 ◽  
Author(s):  
Jiho Yoo ◽  
Allan J. Jacobson
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Transport ◽  
Diffusion Coefficients ◽  
Abrupt Change ◽  
Vacancy Diffusion ◽  
Conductivity Relaxation ◽  
Surface Exchange ◽  
Electrical Conductivity Relaxation ◽  
Oxygen Ion ◽  
Thermodynamic Factors

ABSTRACTExperimental results from electrical conductivity relaxation (ECR) measurements on SrFeO3-x are described. Values of Dchem and kchem were obtained by monitoring the variation of the time dependence of the electrical conductivity after an abrupt change in the oxygen partial pressure. Values for the oxygen ion and vacancy diffusion coefficients were calculated from the measured thermodynamic factors and compared with those of other compositions in the series La1-xSrxFeO3-x. The surface exchange coefficients, kchem and kex were also determined.

scholarly journals Chemical surface exchange of oxygen on CeO2−δ in an O2/H2O atmosphere

2017 ◽  
Vol 19 (43) ◽  
pp. 29287-29293
Author(s):  
Ho-Il Ji ◽  
Xin Xu ◽  
Sossina M. Haile
Keyword(s):  
Electrical Conductivity ◽  
Relaxation Method ◽  
Parallel Process ◽  
Conductivity Relaxation ◽  
Surface Exchange ◽  
Chemical Surface ◽  
Electrical Conductivity Relaxation

As measured by the electrical conductivity relaxation method, oxidation of undoped ceria at 1400 °C under moist oxygen proceeds in a parallel process of uncorrelated oxidation by H2O and by O2.

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