Interface engineering of yttrium stabilized zirconia/gadolinium doped ceria bi-layer electrolyte solid oxide fuel cell for boosting electrochemical performance

Abstract

La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) is a promising cathode material for solid oxide fuel cells due to its high oxygen reduction reaction (ORR) activity. A gadolinium-doped ceria (GDC) barrier layer is essential to preventing side reactions between LSCF and an yttrium-stabilized zirconia (YSZ) electrolyte. However, several challenges are associated with the coating of GDC barrier layer on the YSZ electrolyte, including delamination of the GDC layer due to sinterability differences and formation of an insulating layer at a high annealing temperature. In this study, we describe a structure for a newly designed interfacial layer consisting of a GDC barrier layer and a nano-web–structured LSCF thin-film layer (NW-LSCF) through a facile spin-coating method. A dense GDC barrier layer with a thickness of approximately 400 nm was successfully applied to the surface of a YSZ electrolyte without delamination at a low annealing temperature. The high surface area of the NW-LSCF enhanced ORR due to an increased triple-phase boundary length. Cells employing a GDC barrier layer and NW-LSCF interlayer exhibited improved electrochemical performance. Peak power density reached 1.29 W/cm2 at an operating temperature of 550 °C and 2.14 W/cm2 at 650 °C.