Processing of manganite-based contact layers for stacking of planar solid oxide fuel cells

Abstract

Quality of the solid oxide fuel cell (SOFC) stack assembly affects power density and lifetime of the power plants. In the case of planar SOFCs, assembling quality depends on electrical contact between the stainless steel current collectors and ceramic electrodes of the membrane-electrode assemblies (MEAs). Whilst Ni meshes and paste are commonly used to provide this contact at the anode side, the cathode contact materials should be stable in oxidizing atmosphere. In this work, mechanical pre-treatment conditions of submicron La0.8Sr0.2MnO3±δ (LSM) cathode powders were optimized in order to sinter mechanically stable contacts in the course of SOFC sealing procedure without use of inorganic sintering aids. Excessive ball-milling time and/or rotating speed was shown to result in partial decomposition of the perovskite phase, which increases electrical resistivity of the porous layers. Testing of the LSM contact layers in model SOFC stack with Crofer 22H current collectors under standard operating conditions demonstrated sufficient adhesion and performance.