International Journal of Hydrogen Energy, Vol.45, No.25, 13625-13642, 2020
Transport properties of Ca-doped Ln(2)NiO(4) for intermediate temperature solid oxide fuel cells cathodes and catalytic membranes for hydrogen production
Novel methods were applied in this work to elucidate the structure evolution of Ln(2-x)Ca(x)NiO(4+delta) oxides (Ln = La, Pr, Nd; x = 0, 0.3) and study their oxygen mobility. Relationship between cations state, structural, electrical, electrochemical and kinetic properties was revealed. In all doped materials the overall oxygen mobility characterized by Do declined by more than an order of magnitude due to decreasing the interstitial oxygen content and hampering cooperative mechanism of oxygen migration. For La nikelate additional slow diffusion channel appears with D-O 5.4.10(-14) cm(2)/s at 700 K. Correlation of electrochemical and oxygen transport properties was demonstrated. A high electrical conductivity (up to 120 S/cm at 700 K) in Ln(1.7)Ca(0.3)NiO(4+delta) (Ln = Pr, Nd) along with satisfactory oxygen mobility and electrochemical properties makes these materials promising for a wide row of electrochemical applications. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.