Towards designing La 1−x Sr x Co y Fe 1−y O 3−d with enhanced phase stability: Role of the defect structure

Emmerlich, Jens; Linke, Bernd M.; Mušić, Denis; Schneider, Jochen M.

doi:10.1016/j.ssi.2013.11.047

Cited by 14 publications

(9 citation statements)

References 42 publications

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“…Lattice constant is affected by compositions and stoichiometry. More atoms in A-sites lead to smaller lattice constant [36]. Smaller lattice constant can lead to larger conductivity.…”

Section: Fundamental Cathode Behaviorsmentioning

confidence: 99%

Perovskite-type La0.6Sr0.4Co0.2Fe0.8O3, Ba0.5Sr0.5Co0.2Fe0.8O3, and Sm0.5Sr0.5Co0.2Fe0.8O3 cathode materials and their chromium poisoning for solid oxide fuel cells

Shen

2016

Electrochimica Acta

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A B S T R A C TIn the pursuit for solid oxide fuel cell (SOFC) cathode materials that can operate over a wide temperature range, especially at low temperatures such as 600 C, perovskite structure materials La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF), Ba 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 (BSCF), and Sm 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 (SSCF) are studied. Their electrochemical performance is compared by electrochemical impedance spectroscopy (EIS) at 600 C, 700 C and 800 C for 100 hrs through an AISI 441 interconnect/cathode/yttria-stabilized zirconia (YSZ) electrolyte half-cell structure. The BSCF cathode has the smallest polarization resistance at 600 C, closely followed by the SSCF cathode; the LSCF cathode has the smallest polarization resistance working at 700 C; the SSCF cathode has the smallest polarization resistance working at 800 C, closely followed by the LSCF cathode. From 600-800 C, SrCrO 4 phase forms on the SSCF cathodes near the interconnect while BaCrO 4 phase forms on the BSCF cathodes near the interconnect. For the LSCF cathodes, however, SrCrO 4 phase is only detected at 700 C and 800 C. Cr species diffusion to and poisoning of the cathodes do not directly correlate with the half-cell performance. Lattice constant, stoichiometry, particle size, Cr deposition, and working temperature are important factors to consider.

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“…Lattice constant is affected by compositions and stoichiometry. More atoms in A-sites lead to smaller lattice constant [36]. Smaller lattice constant can lead to larger conductivity.…”

Section: Fundamental Cathode Behaviorsmentioning

confidence: 99%

Perovskite-type La0.6Sr0.4Co0.2Fe0.8O3, Ba0.5Sr0.5Co0.2Fe0.8O3, and Sm0.5Sr0.5Co0.2Fe0.8O3 cathode materials and their chromium poisoning for solid oxide fuel cells

Shen

2016

Electrochimica Acta

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“…The (110) peak shift is due to the ionic radius difference from La 3+ (1.36 Å), Ba 2+ (1.61 Å), and Sm 3+ (1.24 Å) with the relationship of Ba 2+ >La 3+ >Sm 3+ . The lattice parameters of the synthesized perovskite LSCF, BSCF, and SSCF are calculated to be 3.8666 Å, 3.9495 Å, and 3.8410 Å, respectively, which are smaller than the reported values, 3.8973 Å[29], 3.9554 Å[14], and 3.8547 Å[18] but are fairly close.…”

mentioning

confidence: 67%

Comparative study of La0.6Sr0.4Co0.2Fe0.8O3, Ba0.5Sr0.5Co0.2Fe0.8O3 and Sm0.5Sr0.5Co0.2Fe0.8O3 cathodes and the effect of Sm0.2Ce0.8O2 block layer in solid oxide fuel cells

Shen

2015

International Journal of Hydrogen Energy

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In the pursuit for solid oxide fuel cell (SOFC) cathode materials which can perform better at 800 o C, perovskite structure materials La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF), Ba 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 (BSCF), and Sm 0.5 Sr 0.5 Co 0.2 Fe 0.8 O 3 (SSCF) are studied. Their electrochemical performance as the cathodes is compared by electrochemical impedance spectroscopy (EIS) at 800 o C for 100 hrs through an AISI 441 interconnect/cathode/yttria-stabilized zirconia (YSZ) electrolyte half-cell structure. SSCF cathode has the smallest polarization resistance and is the most desired cathode at 800 o C while BSCF cathode has the largest one. SrCrO 4 phase forms on the LSCF and SSCF cathodes near the interconnect, but not on the BSCF cathode. With the spin coating of ~3 µm thick Sm 0.2 Ce 0.8 O 2 (SDC) block layer on the YSZ electrolyte, the polarization resistances of the three cathode materials all decrease. The SDC layer can effectively decrease the mismatch of the thermal expansion coefficients (TECs) between BSCF and YSZ.

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“…Most recently the application of plasma and electrical depositions in surface modification and sol-gel in B-site substitution has been tried and instead of noble metal, more transition metals are used, especially on B-site substitution. Moreover, even in the case of excellent properties of fresh LSCF cathodes, the chemical and thermal stability under operating condition is an important issue to be addressed for practical applications [51,74,75]. A study of Ni-YSZ/YSZ/GDC/LSCF-Ag cell showed that the good initial performances of Ag infiltrated cathodes are maintained after 150 h operation at 730 °C ( Figure 10 [36]).…”

Section: Discussionmentioning

confidence: 99%

B-Site Metal (Pd, Pt, Ag, Cu, Zn, Ni) Promoted La1−xSrxCo1−yFeyO3–δ Perovskite Oxides as Cathodes for IT-SOFCs

Guo

Puleo

et al. 2015

Catalysts

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Perovskite oxides La1−xSrxCo1−yFeyO3-δ (LSCF) have been extensively investigated and developed as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) due to mixed ionic-electronic conductivity and high electrooxygen reduction activity for oxygen reduction. Recent literature investigations show that cathode performances can be improved by metal surface modification or B-site substitution on LSCF. Although the specific reaction mechanism needs to be further investigated, the promoting effect of metal species in enhancing oxygen surface exchange and oxygen bulk diffusion is well recognized. To our knowledge, no previous reviews dealing with the effect of metal promotion on the cathodic performances of LSCF materials have been reported. In the present review, recent progresses on metal (Pd, Pt, Ag, Cu, Zn, Ni) promotion of LSCF are discussed focusing on two main aspects, the different synthesis approaches used (infiltration, deposition, solid state reaction, one pot citrate method) and the effects of metal promotion on structural properties, oxygen vacancies content and cathodic performances. The novelty of the work lies in the fact that the metal promotion at the B-site is discussed in detail, pointing at the effects produced by two different approaches, the LSCF surface modification by the metal or the metal ion substitution at the B-site of the perovskite. Moreover, for the first time in a review article, the importance of the combined effects of oxygen dissociation rate and interfacial oxygen transfer rate between the metal phase and the cathode phase is addressed for OPEN ACCESSCatalysts 2015, 5 367 metal-promoted LSCF and compared with the un-promoted oxides. Perspectives on new research directions are shortly given in the conclusion.

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Towards designing La 1−x Sr x Co y Fe 1−y O 3−d with enhanced phase stability: Role of the defect structure

Cited by 14 publications

References 42 publications

Perovskite-type La0.6Sr0.4Co0.2Fe0.8O3, Ba0.5Sr0.5Co0.2Fe0.8O3, and Sm0.5Sr0.5Co0.2Fe0.8O3 cathode materials and their chromium poisoning for solid oxide fuel cells

Perovskite-type La0.6Sr0.4Co0.2Fe0.8O3, Ba0.5Sr0.5Co0.2Fe0.8O3, and Sm0.5Sr0.5Co0.2Fe0.8O3 cathode materials and their chromium poisoning for solid oxide fuel cells

Comparative study of La0.6Sr0.4Co0.2Fe0.8O3, Ba0.5Sr0.5Co0.2Fe0.8O3 and Sm0.5Sr0.5Co0.2Fe0.8O3 cathodes and the effect of Sm0.2Ce0.8O2 block layer in solid oxide fuel cells

B-Site Metal (Pd, Pt, Ag, Cu, Zn, Ni) Promoted La1−xSrxCo1−yFeyO3–δ Perovskite Oxides as Cathodes for IT-SOFCs

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