Performance Enhancement of La 0.3 Ca 0.7 Fe 0.7 Cr 0.3 O 3-δ Air Electrodes by Infiltration Methods

Abstract

© The Author(s) 2017. Published by ECS. Our recent studies have shown that La 0.3 Ca 0.7 Fe 0.7 Cr 0.3 O 3- δ (LCFCr) is an extremely promising material for use as an air electrode in reversible solid oxide cells (RSOFCS), due to its excellent activity towards the oxygen reduction and evolution reactions. LCFCr has also been shown to be a very active catalyst for CO 2 /CO reactions at the fuel electrode, thus making it a good candidate for use in symmetrical RSOFCs. In the present work, GDC and GDC + LCFCr polymeric precursor solutions were infiltrated into a porous LCFCr scaffold to further enhance the performance, producing a high surface area, nanoporous coating on the LCFCr surface. GDC infiltration resulted in a ca. 2-fold decrease in polarization resistance, specifically lowering the high frequency resistance, which is associated with the electrode/electrolyte interface. When the porous LCFCr electrode structure was co-infiltrated with GDC + LCFCr, the resistance of both the high and low frequency processes decreased, which according to our model, indicates that the quality of both the electrode/ele ctrolyte (high frequency) and solid/gas (low frequency) interfaces were improved. Overall, it was shown to be possible to reduce the polarization resistance of the LCFCr air electrode by up to ca. 2.5 times using these infiltration approaches.