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 La9.66Si5.3B0.7O26.(14) (c-LSBO) solid electrolyte cell. A significant increase in the oxygen permeation flux is observed on applying a DC voltage of >= 4V at temperatures <600 degrees C. A remarkably high flux of 5.2 mL cm(-2) min(-1) is obtained even at 500 degrees 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. (C) The Author(s) 2021. Published by ECSJ.

Automated summary

This study demonstrates the potential of an oxide-ion-conductor-based oxygen pumping system as an on-site oxygen separation system, by observing the oxygen permeation capability in a Pt electrode/L-SDC/L-LSBO solid electrolyte cell. The results show a significant increase in oxygen permeation flux under applied DC voltages, with a remarkably high flux even at 500 degrees C. In situ X-ray diffraction studies reveal the changes in L-SDC under applied voltages, leading to the formation of a mixed electron- and oxide-ion-conducting L-SDC electrode and enhancing oxygen reduction reaction and incorporation.