Silver Based Perovskite Nanocomposites as Combined Cathode and Current Collector Layers for Solid Oxide Fuel Cells

Abstract

Properties of silver at elevated temperatures limit its use as a porous electrode or current collector in solid oxide fuel cell (SOFC) configurations. Its relatively low melting temperature (962°C) leads to accelerated densification of silver at operating temperatures of intermediate temperature SOFCs (550°C–800°C). In previous studies, powder based silver composites demonstrated stable microstructures with desirable porosity and electrical conductivity during long-term testing. Although the characterized features of the silver based composites allowed their use as efficient and stable cathode current collectors, they demonstrated limited electrochemical performance as a cathode layer. In this study, nanostructured coatings of various perovskite based cathode materials (lanthanum-strontium manganite (LSM), lanthanum-strontium ferrite (LSF), lanthanum-strontium cobalt-ferrite (LSCF)) were deposited into porous silver composites by infiltration of polymeric precursors to enhance their electrode efficiencies. As a result, novel metal-matrix perovskite nanocomposites were obtained. The properties of the Ag based nanocomposites allowed their use as a combined cathode and current collector layer with significantly improved electrochemical performance and long term stability at 800°C in air.