Papers by Keyword: Oxide Ion

Abstract: K2NiF4 type oxides have received considerable attention in recent years as possible mixed conducting membranes for technologically important applications such as solid oxide fuel cells and oxygen generators. Much of this interest has focused on the oxygen interstitial containing oxides such as La2NiO4+δ. This contribution will review some of the recent work on these and related materials and will present new data on the La2MO4+δ (M= Ni, Co or Mn) systems. In particular data on the oxide ion diffusivity of these systems, as determined by oxygen isotopic exchange and SIMS analysis highlighting the fast oxide ion diffusion (1 x 10-7 cm2s-1 at 750oC) present, will be discussed and the significance of these data evaluated in relation to solid oxide fuel cell systems. A further section of the presentation will consider the oxygen defect species present and discuss the nature of the mobile oxygen ions. Finally some preliminary data on the application of these materials as cathodes will be presented and the performance of the cathodes on intermediate temperature electrolytes discussed.

Abstract: The O2-gas electrode (OGE) properties of the perovskite-related oxides SrFe1-x-yCoyRuxO3 (SFCR) were examined with the solid-state cells of the type (SFCR | Ba0.975Ce0.8Gd0.2O3 | SFCR) below 300°C. The SrFe0.7Co0.2Ru0.1O3 electrode showed the best OGE properties of the other SrFe1-x-yCoyRuxO3 (x
0.2) electrodes prepared here. An oxide-ion current of 200 μA/cm2 was allowed to flow through the cell with the SFCR electrode at 225°C. The SFCR electrodes including some other compositions can be used instead of conventional Pt electrodes in solid-state cells at temperatures below 300°C.

Abstract: The O2-gas electrode (OGE) properties of the pyrochlores Pb2Ru2-XMXO7-δ(M=Mn,Fe,Co,Ni) [PRMx] were examined below 300°C with the cell of the type (PRMx | Ba0.975Ce0.8Gd0.2O3 (BCG) | PRMx). The PRMn electrodes showed good OGE properties comparable to those of Pb2Ru2O6.5 and superior to those of a Pt-paste electrode and the La0.6Sr0.4Co0.98Ni0.02O3 electrode, which are well-known representative OGEs. The results indicate that the PRMn electrodes can be used for OGEs in low-temperature applications including oxygen sensors.