A highly active and Cr-resistant infiltrated cathode for practical solid oxide fuel cells

Abstract

A critical obstacle to the commercialization of modern solid oxide fuel cells (SOFCs) loaded with metallic interconnects is the unacceptable degradation rate resulting from Cr (an element richly present in metallic interconnects) volatilization and its subsequent reaction with the cathode, forming insulating SrCrO₄ that blocks oxygen reduction reaction (ORR) active sites. Here we report a Cr-tolerant, yet ORR-active, cathode for sustainable operation of solid oxide fuel cells (SOFCs). The new resilient cathode consists of a continuous, nanoscaled, ORR-active SrCo_0.9Ta_0.1O_3−δ (SCT) as the capping layer and a commercial (La_0.6Sr_0.4)_0.95Co_0.2Fe_0.8O_3−δ (LSCF)–Ce_0.8Gd_0.2O_1.9 (GDC) composite as the underlying skeleton. Stability testing in a high-Cr-content environment shows that the cathode has a remarkable resistance to Cr-attack while retaining superior ORR activity. A successful implantation of this bilayer cathode into practical SOFC stacks will advance the commercialization of SOFC technology.