Influence of Electrolyte Scaffold Microstructure and Loading of MIEC Material on the Electrochemical Performance of RSOC Fuel Electrode

Abstract

AbstractPerovskite‐based mixed ionic electronic conductive (MIEC) oxides have been synthesized and studied as promising redox‐stable solid oxide cell (SOC) electrode materials. In order to enhance performance of MIEC electrode materials, influence of porous electrolyte structure as well as the loading of the electroactive material on the performance of La0.8Sr0.2Cr0.49Mn0.49Ni0.02O3‐δ – (Sc2O3)0.1(CeO2)0.01(ZrO2)0.89 (LSCMN‐ScCeSZ) and Sr2Fe1.5Mo0.5O6‐δ (Sc2O3)0.1(CeO2)0.01(ZrO2)0.89 (SFM‐ScCeSZ) MIEC electrodes have been studied. The results indicated that pre‐calcination and milling process of ScCeSZ electrolyte powder increased the average pore sizes and the overall porosity of scaffolds by about 10 vol.%. However, due to the use of pre‐calcined electrolyte powder with increased particle sizes, specific area of electrolyte scaffolds and catalytic activity decreased at lower MIEC loadings. Porous scaffold with highest open porosity of 81% was used to study the influence of different MIEC materials at high loadings on the performance of composite electrodes. Results indicated that optimal loading depends on the properties of MIEC material and it was found to be 30 and 50 wt.% for SFM and LSCMN, respectively. The highest current density values 1.11 and 0.78 A cm−2 were measured for electrolysis mode at 850 °C, at potential 1.5 V and 30% of absolute humidity for SFM and LSCMN composite electrodes, respectively.