KINETICS OF INTERFACIAL OXYGEN-EXCHANGE IN THE SYSTEM O2 LA0.7SR0.3COO3-DELTA/MONOCRYSTALLINE ELECTROLYTE BASED ON ZRO2/

The interfacial oxygen exchange rate in the O2/La0.7Sr0.3CoO3-delta/mo nocrystal 0.91ZrO2 + 0.09Y2O3 electrode system was measured by the iso topic exchange method. The temperature dependence of the rate was adeq uately studied at temperatures ranging from 1000 to 1200 K and oxygen pressures ranging from 3 to 19 torr. The data we obtained were explain ed in the following supposition: the most rapid exchange of electrolyt e oxygen takes place with participation of the cobaltite surface in th e zone of the three-phase electrolyte/electrode/gas boundary. It is al so suggested that the effective area for oxygen exchange changes rever sibly with variations in temperature. The limiting stage of the oxygen exchange in the electrode system is localized on the cobaltite surfac e.