Highly-Conductive and Durable SOFC Cathode-Side Contact Based on Reactively-Sintered Mn-Co Spinel

Abstract

A cathode-side contact layer with well-matched coefficient of thermal expansion is needed to prevent cracking of solid oxide fuel cell stacks from thermal cycling during stack operations. An Mn1.25Co1.75O4 (MCO) spinel layer synthesized via reactive sintering with a metal-containing precursor was proposed as a highly conductive and durable contact material. Compared to the interconnect/contact/cathode assemblies with the (La0.80Sr0.20)0.95MnO3-x and La(Mn0.45Co0.35Cu0.2)O3 contacts, the assembly with the MCO contact exhibited the lowest area-specific resistance at 800 °C (8.2 mΩ·cm2) during 2000-h cyclic exposure and was crack-free based on the cross-sectional examination, indicative of the superiority of the spinel contact over the perovskite counterparts.