Interface Stability among Solid Oxide Fuel Cell Materials with Perovskite Structures

Abstract

The chemical stability of the interface of lanthanum strontium iron cobalt oxides (LSCF) and lanthanum strontium magnesium gallium oxide (LSGM) was investigated. LSCF and LSGM do not coexist stably, and it makes solid solutions at higher temperatures by the fast interdiffusion of metal components. The bulk and grain boundary diffusivities were determined as a function of temperature for LSGM, LSCF, and lanthanum strontium manganite current collectors. The activation energies of bulk diffusivity of Co or Fe in LSGM or LSM, and Mn in LSCF are around 500kJmol−1 . The effect of grain boundary as a fast diffusion path was clearly visualized for manganese diffusion in LSCF.

Electrochemical evaluation of La0.6Sr0.4Co0.8Fe0.2O3−δ–La0.9Sr0.1Ga0.8Mg0.2O3−δ composite cathodes for La0.9Sr0.1Ga0.8Mg0.2O3−δ electrolyte SOFCs

“…Above 1100 • C the peaks of the spectra exhibit a significant shift, indicating that LSCF strongly reacted with LSGM, which fact was similar to previous reports [23]. It is assumed that the high diffusivity of the metal cations in LSGM is attributed to the feature of perovskite structure which has a large flexibility and can readily accept a variety of cations [12]. High temperature definitely promotes this diffusion causing reactions between the two composites.…”

“…5 [11]. Sakai et al investigated the chemical stability of the interface of lanthanum strontium iron cobalt oxides (LSCF) and LSGM, and reported that LSCF and LSGM do not coexist stably at higher temperatures (annealed at 1100 • C for 5 h) due to formation of solid solutions by the fast inter-diffusion of metal components [12]. They revealed that the diffusion of metal components is not avoidable at the interface of LSCF/LSGM and the bulk diffusivities of Mg or Ga in LSCF also increased with temperature.…”

Thermodynamic and kinetic considerations on degradations in solid oxide fuel cell cathodes

“…The present results on the perovskite/doped ceria interface should be compared first with results of diffusion couple experiments [45,46] associated with perovskite cathodes and doped ceria, and then with the materials behavior under the operation of electrochemical cells. Finally, it should be investigated how they are correlated with the degradation behavior of cathodes operated with an interlayer of doped ceria.…”

Lanthanum gallate and ceria composite as electrolyte for solid oxide fuel cells

“…Ce 4+ , and thus it is superior to ceria at low oxygen partial pressures. Nevertheless the doped LaGaO 3 has the disadvantage of chemical instability with electrode materials, for example, inter-diffusion of metal components was widely reported at the interface between LSGM electrolyte and the perovskite cathode materials [10][11][12].…”