Interface chemistry in LSM–YSZ composite SOFC cathodes

Backhaus‐Ricoult, M.

doi:10.1016/j.ssi.2006.08.011

Cited by 98 publications

(65 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The two temperature ranges for the water exchange with LSM are consistent with the change of stability of valance states of manganese, [49][50][51][52][53][54] and at these temperature ranges, Mn in the B site of ABO 3 shows the ability to actively change valence states. The contour plot of water exchange with LSCF as a function of PO 2 and temperature are shown in Figure 10.…”

Section: Resultssupporting

confidence: 55%

Fundamental Impact of Humidity on SOFC Cathode ORR

Huang

Pellegrinelli

Wachsman

2015

J. Electrochem. Soc.

View full text Add to dashboard Cite

Although solid oxide fuel cells (SOFC) have demonstrated excellent performance, the durability of SOFCs under real working conditions is still an issue for commercial deployment. In particular cathode exposure to atmospheric air contaminants, such as humidity, can result in long-term performance degradation issues. Therefore, a fundamental understanding of the interaction between water molecules and cathodes is essential to resolve this issue and further enhance cathode durability. To study the effects of humidity on the oxygen reduction reaction (ORR), we used in-situ 18 O isotope exchange techniques to probe the exchange of water with two of the most common SOFC cathode materials, (La 0.8 Sr 0.2 ) 0.95 MnO 3±δ (LSM) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF). In this experiment, heavy water, D 2 O (with a mass/charge ratio of m/z = 20), is used to avoid the overlapping of H 2 O and the 18 O 2 cracking fraction, which both provide a peak at m/z = 18. A series of temperature programmed isotope exchange measurements were performed to comprehensively study the interaction of water with the cathode surface as a function of temperature, oxygen partial pressure, and water vapor concentration. The results suggest that water and O 2 share the same surface exchange sites, leading to competitive adsorption. Our findings show that water prefers to exchange with LSCF at lower temperatures, around 300-450 • C. For LSM, O 2 is more favorable than water to be adsorbed on the surface and the presence of O 2 limits water exchange. The experimental data are summarized in a Temperature-PO 2 diagram to help visualize how the exchange of water on each material depends on the operating conditions. © The Author Solid oxide fuel cells (SOFC) electrochemically oxidize fuels for the generation of electricity. Two key advantages of SOFCs are their high efficiency and ability to utilize conventional fuels. This fuel flexibility stems from the dissociation and transport of oxygen from the cathode through the electrolyte to the anode, where the fuels are oxidized. Unfortunately, cathode degradation under real working conditions is a factor that limits SOFC performance. 1-6The long term durability of these materials is a major challenge, due to the high temperature required for the thermally activated oxygen reduction reaction (ORR), 7 as well as the variety of gases present during operation. 8,9 The impurities present in air on the cathode side of the cell can induce undesirable reactions. Some of these impurities, such as Cr or silica, 10-15 arise due to the interconnect and seal materials while some are intrinsic to ambient air, such as humidity and CO 2 . 16 Humidity has been found to degrade the performance of (La 0.8 Sr 0.2 ) 0.95 MnO 3±δ (LSM) and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) based cells. 11,[17][18][19][20][21][22][23][24] This degradation can be either reversible or irreversible. 21 However, there is no conclusive evidence showing, fundamentally, how water participates in the degradation process, and it is hard to quan...

show abstract

Section: Resultssupporting

confidence: 55%

Fundamental Impact of Humidity on SOFC Cathode ORR

Huang

Pellegrinelli

Wachsman

2015

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…4). According to Backhaus-Ricoult [26], there is a substantial interdiffusion across the LSM-YSZ interface with the formation of highly doped zirconia. The diffusion coefficients of ions at the LSM-YSZ interface follow the order: D Sr  D La <D Mn .…”

Section: Morphology and Microstructure Of The Ysz Filmsmentioning

confidence: 99%

Characterization of yttria-stabilized zirconia films deposited by dip-coating on La0.7Sr0.3MnO3 substrate: Influence of synthesis parameters

Marrero¹,

Ribeiro²,

Malfatti³

et al. 2013

J Adv Ceram

View full text Add to dashboard Cite

Yttria-stabilized zirconia (YSZ, ZrO 2 -8%Y 2 O 3 ) films were deposited onto lanthanum strontium manganite (LSM, La 0.7 Sr 0.3 MnO 3 ) substrates using dip-coating process aiming for the application in solid oxide fuel cells (SOFCs). YSZ precursor was prepared by sol-gel method; three values of the organic/inorganic concentration ratio (1, 3 and 5) were utilized and the sol viscosity was adjusted (60 mPa·s and 100 mPa·s) before deposition on the substrate. The influence of these synthesis parameters on the structure and morphology of the deposited films was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The films showed characteristic peaks of LSM, YSZ (with cubic structure) and secondary phases of SrZrO 3 and La 2 O 3 . Depending on the synthesis conditions, crack-free, homogeneous and well adhered films were obtained, with thickness of 11-24 m.

show abstract

“…In a recent review of solid state chemistry applied to SOFC materials Backhaus-Ricoult [10,32] studied different solid oxide cathodes with Zirconia based electrolytes. The author found that formation of reaction products, diffusion, segregation and modification of the electronic structure in the cathode/electrolyte interphase affected the Oxygen exchange rate and had an undesirable impact on the SOFC performance.…”

Section: Reactivity At the Interphasementioning

confidence: 99%