Study on the Cr deposition and poisoning phenomenon at (La0.6Sr0.4)(Co0.2Fe0.8)O3-d electrode of solid oxide fuel cells by transmission X-ray microscopy

Abstract

Herein, Cr deposition and poisoning behavior at the commonly used (La0.6Sr0.4)(Co0.2Fe0.8)O3d (LSCF) electrode of solid oxide fuel cells (SOFCs) is investigated. Three-dimension (3D)microstructure evolution of the porous electrode caused by Cr deposition during the polarizationtest at 900 C in the presence of a FeeCr metallic interconnect is characterized forthe first time using the transmission X-ray microscopy (TXM) technique. The resultsindicate that a layer of solid Cr deposits ~1.7 mm in thickness is formed on the electrodesurface, significantly reducing the linear porosity to ~2% in the surface region from ~25%in the bulk, which explains the retarded gas diffusion process at the LSCF electrode after Crdeposition. The well-established relationship between the macroscopic performancedegradation and the microstructure evolution confirms the promising application of TXMtechnique for in-depth study of the degradation phenomenon at the electrode of SOFCs.