Open AccessElectrochemical Operation of La(Ni,Fe)O3 under Cr-Poisoning Conditions
Author(s) -
Maciej K. Stodolny,
Bernard A. Boukamp,
Dave H. A. Blank,
F.P.F. van Berkel
Publication year - 2013
Publication title -
ecs transactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.235
H-Index - 52
eISSN - 1938-6737
pISSN - 1938-5862
DOI - 10.1149/05027.0133ecst
Subject(s) - materials science , overpotential , cathode , electrochemistry , ohmic contact , electrode , chemical engineering , conductivity , layer (electronics) , composite material , analytical chemistry (journal) , chemistry , chromatography , engineering
This study demonstrates the significant impact of Cr-poisoning on the electrochemical operation of the LaNi 0.6 Fe 0.4 O 3 (LNF) SOFC cathode under current load. Volatile Cr-species, originating from a porous metallic foam, enter the working electrode and modify both the LNF cathode layer and the Gd 0.4 Ce 0.6 O 1.8 (GDC) barrier layer, causing increasing overpotential and cell impedance. The increase of the ohmic resistance is caused by a decrease of the in-plane electronic conductivity of the LNF layer combined with a deterioration of the ionic conductivity of the GDC barrier layer. The increase of the polarisation resistance is caused by a decrease of the electrochemical activity of the LNF surface towards oxygen reduction reaction at the triple phase boundary (TPB) due to Cr-incorporation in the outer shell of the LNF grains. Chemical reaction and electrochemically-driven reaction of volatile Cr-species with LNF and GDC contributes to the extrinsic degradation of the LNF cathodes under current load.
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