DC-voltage-induced high oxygen permeation through a lanthanum silicate electrolyte with a cerium oxide thin film

An oxide-ion-conductor-based oxygen pumping system can serve as an on-site oxygen separation system. Herein, we present the oxygen permeation capability of a Pt electrode/La-Sm-doped CeO₂ (L-SDC) intermediate layer/c-axis-oriented La_9.66Si_5.3B_0.7O_26.14 (c-LSBO) solid electrolyte cell. A significant increase in the oxygen permeation flux is observed on applying a DC voltage of;4 V at temperatures <600 °C. A remarkably high flux of 5.2 mL cm^-2 min^-1 is obtained even at 500 °C. Furthermore, in situ X-ray diffraction studies under applied voltages reveal an increase in the lattice constant of L-SDC, accompanied by a drastic increase in the oxygen permeation flux, indicating the reduction of Ce⁴⁺ and formation of oxygen vacancies. These results suggest that the observed change in L-SDC under the applied voltage results in the in situ formation of a mixed electron- and oxide-ion-conducting L-SDC electrode, indicating that the oxygen reduction reaction and incorporation is significantly enhanced.