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Cationic Interdiffusion at the SOFC Electrolyte/Cathode Interface in La 2 Mo 2 O 9 /La 0.8 Sr 0.2 MnO 3‐δ
Author(s) -
Ravella Uday K.,
Liu Jingjing,
Corbel Gwenaël,
Skinner Stephen J.,
Lacorre Philippe
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201701180
Subject(s) - diffusion , analytical chemistry (journal) , cathode , electrolyte , pellets , solid oxide fuel cell , materials science , grain boundary diffusion coefficient , oxide , diffusion layer , secondary ion mass spectrometry , ionic bonding , chemistry , ion , layer (electronics) , electrode , thermodynamics , metallurgy , microstructure , nanotechnology , composite material , grain boundary , physics , organic chemistry , chromatography
In this work cation diffusion between a La 2 Mo 2 O 9 (LM) ionic conductor and the conventional Solid Oxide Fuel Cell (SOFC) cathode material La 0.8 Sr 0.2 MnO 3‐δ (LSM), was probed using secondary ion mass spectrometry (SIMS), and diffusion coefficients of Sr, Mo and Mn cations within both materials evaluated. Diffusion coefficients extracted from samples with a Sr solution deposited on the LM pellets and from a Mo solution deposited on LSM pellets were found to be orders of magnitude higher than the cross‐diffusion through the interface between two dense pellets in direct contact. These differences may be due to uncertainty in determining the interface position, or to a real dependence on the source of the diffusing cation. In the most favorable case, that of pellets in direct contact, extrapolation of diffusion coefficients down to a typical SOFC operating temperature, 800 °C, show that Mo diffusion in LSM (diffusion coefficient ∼ 10 −14 cm 2 .s −1 ) is much higher than Sr or Mn diffusion in LM, and incompatible with use in a SOFC device, unless an efficient buffer layer is used.