Indirect monitoring of mixed conduction in La2NiO4+delta-based systems using impedance spectroscopy

Abstract

The Electrochemical activities of updoped (La2NiO4+delta) and Ba-doped lanthanum nicklate (La1.85Ba0.15NiO4+delta) materials were estimated using impedance spectroscopy and digital image processing. Mixed conduction was evaluated with an ionic-conducting, Gd2O3-doped CeO2 probe. Geometric constriction between the ionic probe and mixed-conducting materials allowed for the relative contribution of ionic conduction with regard to electronic conductivity in terms of polarization losses originating from the interface between the oxygen conductor and the mixed-conduction materials. The electrochemical loss in doped La1.85Ba0.15NiO4+delta was significantly lower than that measured in updoped La2NiO4+delta. Therefore, Ba-doped lanthanum nicklate appears to provide better ionic conduction compared to the updoped material.