Electrochemical Properties of a Zirconia Membrane with a Lanthanum Manganate-Zirconia Composite Electrode and its Oxygen Permeation Characteristics by Applied Currents

An electrochemical oxygen permeating membrane (OPM) is fabricated using Zr0.895Sc0.095Ce0.005Gd0.005O2−δ (ScCeGdZ) as the solid electrolyte and aLa0.7Sr0.3MnO3-bScCeGdZ composite (LZab, electrode) as the electrode. The crystal phase of the electrode and the microstructure of the membrane is investigated with X-ray diffraction and scanning electron microscopy. The electrochemical resistance of the membrane is examined using 2-p ac impedance spectroscopy, and LZ55 shows the lowest electrode resistance among LZ82, LZ55 and LZ37. The oxygen permeation is studied with an oxygen permeation cell with a zirconia oxygen sensor. The oxygen flux of the OPM with LZ55 is nearly consistent with the theoretical value calculated from Faraday’s Law below a critical current. However, it becomes saturated above the critical current due to the limit of the oxygen ionic conduction of the OPM. The OPM with LZ55 has a very high oxygen permeation flux of ~ 3.5 × 10 mol/cms in I = 1.4 A/cm.