Sulphur poisoning of the SOFC cathode material La0.6Sr0.4CoO3-δ

Oxygen tracer diffusion and surface exchange kinetics in Ba0.5Sr0.5Co0.8Fe0.2O3−δ

“…However it is possible to speculate that the segregation of Ba on the surface occurred during the high temperature pre-anneal at 950 °C followed by a transformation to BaSO4 when exposed to the unknown contaminant (presumably SO2) present in the ambient air. The formation of SrSO4 at the surface of La0.6Sr0.4CoO3-δ and La0.58Sr0.4Co0.2Fe0.8O3-δ in SO2-containing atmospheres via a similar mechanism has been reported in the literature [22,23]. The second type of feature were small highly crystalline particles (less than 0.6 µm) located randomly on the sample surface (Figure 4c).…”

Mechanism of SO2 Poisoning on the Electrochemical Activity of LSCF and LSM Electrodes

“…3b), which is in accordance with the XPS results of SrSO 4 (13) and the binding energy of the S 2p 3/2 is 169.0 eV for sulfate. Further studies from the literature also report the formation of strontium sulphate due to the exposure of La 0.6 Sr 0.4 CoO 3-δ to >1ppm SO 2 for 24 h at 700 o C (14). …”

Design and processing parameters of La2NiO4+δ-based cathode for anode-supported planar solid oxide fuel cells (SOFCs)

“…Despite their high mixed ionic-and electronic-conductivity and catalytic activity for the oxygen reduction reaction associated with the Co(III)/Co(IV) transition [5], the practical application of a cobalt-rich cathode is still questionable because, in addition to the high costs, the flexible redox behavior of cobalt leads to a number of technical issues such as a high thermal expansion coefficient, poor chemical stability and a high reactivity with zirconia-based electrolyte [6,7]. Moreover, the strontium in an MIEC cathode is largely responsible for performance degradation because the inactive strontium species segregated on the surface interferes the oxygen reduction reaction [8,9] and readily react with gaseous impurity species to form deleterious reaction products such as Sr(OH) 2 [8,10], SrCO 3 [11], SrCrO 4 [12] and SrSO 4 [13]. Therefore, the development of an alternative cobalt-and strontium-free cathode material for intermediate-temperature operation is highly desirable.…”