Study on the strontium segregation behavior of lanthanum strontium cobalt ferrite electrode under compression

摘要

Sr segregation is one of the key issues affecting the performance and durability of lanthanum strontium cobalt ferrite electrode (LSCF) for solid oxide cells (SOCs). In this study, we investigated the Sr segregation behavior in LSCF under compression with purpose of simulating the operating condition of LSCF electrode in an assembled SOC stack. The electrochemical performance of LSCF electrode in a symmetric cell was evaluated by impedance spectrometry. The Sr segregation behavior on the surface of LSCF electrodes was investigated by energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). It was confirmed that the compression load would suppress the formation of SrO on the surface of LSCF during long-term holding in air at 800 degrees C, resulting in significantly improved durability compared with the LSCF electrode without compression. Furthermore, it was revealed that the type of materials (YSZ, GDC and Pt) in contact with LSCF would also affect the Sr segregation in LSCF. In particular, contacting with YSZ under compression would induce more SrO formation on the surface of LSCF than GDC and Pt. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.