High-Temperature Conductivity Measurements of Magnesium-Ion-Conducting Solid Oxide Using Mg Metal Electrodes

The conductivity of polycrystalline pellets of Mg2+-ion-conducting solid oxide Mg0.5−x(Zr1−xNbx)2(PO4)3 (x = 0.15) with monoclinic β-Fe2(SO4)3-type structure was measured with non-blocking Mg metal electrodes at 350 °C in vacuum using a high-temperature cell, which avoided the exposure of Mg electrodes to air before and during the measurements. At 350 °C dc and ac conductivities measured with Mg electrodes were consistent with ac conductivity measured with Pt electrodes. These observations evidenced that this compound is a pure Mg2+-ion conductor and stable in contact with Mg.