OXYGEN PUMPING CHARACTERISTICS OF OXIDE-ION ELECTROLYTES AT LOW-TEMPERATURES

Electrochemical oxygen pumping was employed to study oxygen transport characteristics of electrolytes and electrodes. Oxygen transference nu mbers were measured by measuring volume changes using a liquid column in a capillary. The two electrolytes used were 10 mol% Ca doped CeO2 a nd 20 mol% Sr doped Bi2O3. The electrodes used were Pt, Pd/Au, La0.7Sr 0.3MnO3-delta, La0.5Sr0.5MnO3-delta, and La0.7Sr0.3FeO3-delta. The man ganite perovskite electrode performance was comparable to Pt at 700-de grees-C on both electrolytes. The bismuth electrolyte was found to be reduced to metal on the cathode side at high current densities.