Thermal stability of Ln2NiO4+δ (Ln: La, Pr, Nd) and their chemical compatibility with YSZ and CGO solid electrolytes

Thermal stability and chemical compatibility with electrolyte materials for Solid Oxide Fuel Cells (SOFC) have been studied on Ruddlesden-Popper nickelates Ln(2)NiO(4+delta) with Ln: La, Pr and Nd. Samples of each composition prepared by three different routes, were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Different microstructures were achieved by each preparation method. The thermal stability of these compounds was analyzed by annealing all the samples at 700 and 900 degrees C in air. Pr2NiO4+delta (PNO) decomposes after 24 h of annealing at 700 degrees C confirming its instability at these conditions. Evidences of chemical reaction between La2NiO4+delta (LNO) and both Ce0.9Gd0.1O1.96 (CGO) and Zr0.92Y0.08O1.96 (YSZ) were observed at 700 and 900 degrees C, respectively. No decomposition or chemical reaction with YSZ or CGO were found for Nd2NiO4+delta (NNO) below 900 degrees C. Nevertheless, reactivity with both electrolytes was found for this compound at 1000 degrees C. The kinetics of these reactions strongly depends on the microstructure of Ln(2)NiO(4+delta). Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.