Performance Improvement of an Inhomogeneous Cathode by Infiltration

Abstract

The performance of solid oxide fuel cells (SOFCs) is considerably influenced by the microstructure and chemical composition of cathode materials. Porous La0.85Sr0.15FeO3–Ce0.9Gd0.1O2 composite electrodes were infiltrated by La0.6Sr0.4CoO3 and La0.6Sr0.4FeO3. The effects of infiltration loading, calcination temperature of infiltrated material and co‐infiltration of LSC and LSF were investigated using electrochemical impedance measurement, microstructural analysis, and high‐temperature X‐ray diffraction (HT‐XRD). A symmetrical cell two‐electrode configuration was used to examine the electrochemical performance of the electrodes. The electrochemical results revealed that the polarization resistance of the cathodes significantly was decreased by infiltration from 2.59 to 0.034 Ω cm2 measured at 670 °C. The best electrode performance was achieved at a calcination temperature of 770 °C. It was also found that infiltration of LSC improved the stability of the electrodes during 145 h of testing at 620 °C in air at open circuit voltage (OCV).

Improving oxygen incorporation rate on (La0.6Sr0.4)0.98FeO3-δ via Pr2Ni1-xCuxO4+δ surface decoration

“…Preferred MIEC "backbone" electrodes on which effects of infiltration have been studied are (La0.8Sr0.2)0.95MnO3 (LSM) and LSCF [2]. Due to the significantly better electrochemical performance of Co-substituted ferrite perovskites compared to their non-Co-containing version, many researchers have preferred LSCF over lanthanum strontium ferrite (LSF) as the MIEC backbone for infiltration [1,2,[27][28][29][30][31][32][33][34][35][36][37][38]. Detailed studies on the surface exchange rate on pellet type LSCF has shown that under prolonged exposure to moisturized air at 600 °C, the surface exchange rate strongly decreases, which was attributed to formation of Sr-rich carbonate and silicate phases [39], which are stable at these temperatures.…”

“…The use of the non-Co-containing counterpart offers the advantage of an inherently higher thermochemical material stability in addition to lower cost [32]. LSF is a classic MIEC oxide with perovskite structure, and its properties as a cathode material for SOFCs has previously been studied in some detail [8,[33][34][35][36][37][38]. Also for pure LSF, changes in surface chemistry during long term aging at low temperature (600 °C) may reduce the surface exchange kinetics [8].…”

Nanointegrated, High-Performing Cobalt-Free Bismuth-Based Composite Cathode for Low-Temperature Solid Oxide Fuel Cells

“…Surface modification of cathodes is one of the promising methods to enhance the performance of LT-SOFCs. − Among all surface modification techniques, solution infiltration in porous electrodes is simple and cost effective to enhance surface electrochemical reactions. − However, a high-temperature calcination step is required for the infiltrates to form active phases, e.g., perovskites, and this thermal treatment step diminishes the size advantage of nanoscale infiltrates and lowers the catalytic activity for ORR.…”