Preventing of LaNiO3 Formation at the LSGM-NiO Interface via LDC Protective Layer and Proper Processing Route for Solid Oxide Fuel Cells

Abstract

LSGM based SOFC cells are prone to suffer from performance degradation during operation, when they are used with Ni-containing anodes. In this study, one of the causes for performance degradation in an LSGM-based SOFC system was investigated. XRD and SEM studies coupled with EDX measurements revealed that formation of an insulating LaNiO3 layer is possible in such cells depending on the processing conditions. This ionic insulator phase forms a layer on the anode side of the LSGM and may block oxygen ion diffusion through electrolyte. A possible solution to hinder the formation of LaNiO3 phase is the use of doped ceria (XDC; where X = La or Sm) as a protective layer with proper processing route. Cross-sectional EDX analyses coupled with SEM showed that lanthanum doped ceria (LDC) was a very effective protection layer for LSGM. In contrast to LDC, samarium doped ceria (SDC) protective layer was ineffective. An inexpensive and feasible fabrication procedure for SOFC assembly was demonstrated with a thin (1-5 µm) and dense protective layer-electrolyte couple coated onto the anode.