Synthesis, characterization and electrochemical properties of La2-xEuxNiO4+δ Ruddlesden-Popper-type layered nickelates as cathode materials for SOFC applications

Eu doped La2NiO4 powders, with the general formula La2xEuxNiO4-delta denoted as LENOx (for x = 0, 0.2, 0.4, 0.6 and 0.8), were synthesized via the mechanical milling reaction method. The Eu3+ doping content has a remarkable influence on structural and electrochemical properties. The phase identification and morphology were studied by X-ray diffraction (XRD), Raman spectroscopy, Infrared spectroscopy (IR), A laser size analyzer and scanning electron microscopy (SEM). Lattice parameters were calculated using the Rietveld method. It was observed that the lattice parameter values in LENOx systems varied with the amount of Eu3+. The latter was symmetrically deposited by spin coating on both surfaces of an Ce0.8Sm0.2O1.9 (SDC) electrolyte and studied using AC impedance spectroscopy. The electrochemical properties were studied using two-probe impedance spectroscopy and results showed that the ASR of LENOx was enhanced by the Eu3+ dopant content x. Results also showed that LNEO0.2 had the lowest Area specific resistance (ASR) at 700 degrees C and it was therefore concluded that doping with the appropriate amount of Eu3+ can further improve the properties of a nickelate cathode. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.