Fabrication and Characterization of Strontium-Doped Lanthanum Manganite Cathode Supports for Micro-Tubular Solid Oxide Fuel Cells

Abstract

Strontium-doped lanthanum manganite (LSM) is a preferred cathode material for solid oxide fuel cells (SOFCs) owing to its good electrocatalytic properties for oxygen reduction reaction, high electronic conductivity, and thermal/chemical stability in oxidizing environments. However, for fabricating cathode-supported SOFCs, co-sintering of the electrolyte layer with the LSM support is a challenging step. Although LSM is compatible with the most common zirconia-based electrolytes at SOFC operating temperatures, it reacts with zirconia at higher temperatures to form electrically insulating secondary phases, namely lanthanum zirconate and strontium zirconate. Thus, to avoid the reaction between LSM and zirconia, the co-sintering temperature must be below 1250 °C, which is relatively low for obtaining a dense electrolyte layer. Additionally, it is important to maintain a good porosity of the LSM support to minimize gas diffusion losses through it. In the present work, we attempted to optimize the fabrication process of micro-tubular LSM supports by controlling several parameters such as the slurry composition, pre-sintering temperature, and sintering/co-sintering profiles. The mechanical and electrical properties of the fabricated LSM supports were characterized. Our results are expected to be helpful for achieving high-performance cathode-supported micro-tubular SOFCs with conventional materials.