Improving La0.6Sr0.4Co0.2Fe0.8O3−δ cathode performance by infiltration of a Sm0.5Sr0.5CoO3−δ coating

Lou, Xiaoyuan; Wang, Shizhong; Liu, Ze; Yang, Lei; Liu, Meilin

doi:10.1016/j.ssi.2009.06.014

Cited by 130 publications

(104 citation statements)

References 18 publications

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“…As the result of much higher surface area for oxygen exchange, the effect of rate determining surface exchange kinetics can be limited. Canales-Vazquez et al [33] [34][35][36], LNF cathode [37] and LSM-YSZ composites [38]. All of these materials exhibit much higher electronic conductivities, so results obtained for STFs are interesting.…”

Section: Resultsmentioning

confidence: 97%

Structural and electrical properties of Sr(Ti, Fe)O3-δ materials for SOFC cathodes

et al. 2012

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Doped strontium titanates are very versatile materials. Iron doped SrTiO 3 can be used, for example, as a material for resistive gas sensors and fuel cell electrodes. In this paper, two compositions based on Fe doped SrTiO 3 were studied as possible candidates for cathode application in SOFCs. Namely, SrTi 0.65 Fe 0.35 O 3 and SrTi 0.50 Fe 0.50 O 3 were examined. A chemical reactivity between electrode and YSZ electrolyte material was investigated, since Sr containing cathode materials in contact with YSZ electrolyte are prone to form insulating phases. Electrical conductivity of bulk samples showed relatively low total conductivities of 0.4 S cm −1 and~2 S cm −1 for STF35 and STF50 respectively. Suitability for cathode application was studied by Electrochemical Impedance Spectroscopy in a symmetrical electrode configuration. Area specific resistance (ASR) was determined in the temperature range from 600°C to 800°C. At 790°C samples show polarization ASR of approximately 0.1Ω cm 2 . It can be expected that further reduction of electrode ASR can be obtained by introduction of ceria barrier layer and tailoring of the electrode microstructure.

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Section: Resultsmentioning

confidence: 97%

Structural and electrical properties of Sr(Ti, Fe)O3-δ materials for SOFC cathodes

et al. 2012

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“…For example, the BSCF cathode microstructure might be optimized with better tuning of the firing process and/or introduction of nanostructured catalysts into the BSCF cathode via methods such as infiltration. 18 These would help further increase electrode active surface area and may significantly improve the cathode performance for proton conducting IT-SOFC, and will be studied in future. In addition, it is noted that BSCF was still developed as a "traditional" SOFC cathode materials for conventional oxide-ion conducting SOFC, while some proton-oxide ion-electron "triple conducting" cathode materials have been specifically developed recently for proton-conducting SOFCs and seem to show dramatically improved proton conductivity and electrochemical activity over BSCF.…”

Section: Electrochemical Behavior Of Bscf Anode-supported Full Cell Amentioning

confidence: 99%

Electrochemical Behaviors for Ag, LSCF and BSCF as Oxygen Electrodes for Proton Conducting IT-SOFC

Sun¹,

Cheng²

2017

J. Electrochem. Soc.

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It was found that pure LSCF performs rather poorly like Ag and gives very high interfacial resistance, suggesting sluggish electrode reaction and greatly hindered oxide ion transport between LSCF cathode and BZCYYb electrolyte even under dry condition. In comparison, the LSCF-BZCYYb composite and pure BSCF both show much higher activity toward oxygen electrode reaction, and BSCF outperforms the LSCF composite cathode, suggesting BSCF behaves like a mixed oxide ion-electron conductor in dry atmospheres and a mixed proton-electron conductor in humidified atmospheres. The implication of the experimental observations especially in terms of the similarity and differences in electrochemical behaviors between different electrode materials to the overall cathode reaction mechanism for proton conducting IT-SOFC is discussed, and the directions for further improving the cathode performance for proton conducting IT-SOFC are pointed out.

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“…However, one of the most effective methods of controlling electrode degradation is to modify their surface chemistry using a wet chemical infiltration process, which also leads to an improvement F3115 of the cathodic electrocatalytic activity. [36][37][38] Liu's group studied the effect of LSM infiltrated on LSCF porous electrodes in depth, obtaining improved stability and performances in all cases; 39,40 Zhu et al embedded BSCF cathodes with a dense LSM layer, improving performances and stability, although they limited the investigation to a very short time (18 h). 41 It is worth noting that BSCF has both a high A/B-site cation size mismatch in the ABO 3 perovskite structure and a very low oxygen vacancy formation energy/vacancy migration enthalpy.…”

mentioning

confidence: 99%

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

Giuliano

Carpanese

Clematis

et al. 2017

J. Electrochem. Soc.

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The two half-cell systems were compared to evaluate the influence of infiltration, overpotential and ageing on their performance and stability. Structure, microstructure and chemical composition were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with Energy Dispersive X-ray spectroscopy (EDX), whereas redox behavior was evaluated through temperature programmed reduction (TPR) and thermal gravimetric analysis (TGA) in combination with electrochemical impedance spectroscopy (EIS), which was also used to test the electrochemical performance. A decrease of polarization resistance for both infiltrated electrodes, compared to the reference ones, was highlighted at open circuit voltage (OCV), although the BSCF-based cathode was more benefitted more from infiltration than the LSCF-based one. Moreover, the application of cathodic overpotentials (−0.1 to −0.3 V) resulted in opposite effects on the LSCF-and BSCF-based cathodes, highlighting a different response of the oxygen vacancies to the applied voltage for the two perovskite compositions. The positive effect of the LSM layer was further confirmed by the observed improvement in long-term stability of both infiltrated perovskite-type systems. 1 They exhibit mixed ionic and electronic conductivity, with excellent charge and mass transfer properties 2 and high oxygen exchange surface coefficients. 3 Their excellent activity for oxygen reduction has been proved widely. [4][5][6][7][8][9][10] Although the structure and electrochemical processes of LSCF and BSCF are quite different, both of them have long-term stability and redox behavior issues to be clarified, in order to be used as cathode materials in commercial devices. Indeed, when used as cathodes in intermediate-temperatures solid oxide fuel cells (IT-SOFCs), they suffer from chemical and structural instability, which causes degradation during operation time. Moreover, the correlation between their redox behavior under electrochemical operating conditions is still unclear. Many studies have been devoted to investigating LSCF degradation and several causes have been reported, among them: i) mutual cations diffusion between interfaces with consequent atoms depletion and phase separation, [11][12][13][14][15][16] ii) LSCF grain coarsening, 17 iii) reactivity with YSZ-based electrolytes, even with ceria-based barrier layer, 18 iv) impurity contamination, namely Cr from metal interconnects and B from sealing when the cell is inside a stack.19-21 Some recent work performed on an LSCF/CGO (Ce 0.9 Gd 0.1 O 2-δ ) composite cathode on a YSZ electrolyte with a CGO barrier layer 11 affirms that Sr depletion, phase separation and cations inter-diffusion occur mainly during the fabrication process, with negligible contributions during long-term * Electrochemical Society Member.e Present Address: R&D Manufacturing Support Dept., Ansaldo Energia, Via Nicola Lorenzi 8, I-16152 Genoa. z E-mail: carpanese@unige.it operation (973 K). On the other hand, some previous works conversely found that LS...

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Improving La0.6Sr0.4Co0.2Fe0.8O3−δ cathode performance by infiltration of a Sm0.5Sr0.5CoO3−δ coating

Cited by 130 publications

References 18 publications

Structural and electrical properties of Sr(Ti, Fe)O3-δ materials for SOFC cathodes

Structural and electrical properties of Sr(Ti, Fe)O3-δ materials for SOFC cathodes

Electrochemical Behaviors for Ag, LSCF and BSCF as Oxygen Electrodes for Proton Conducting IT-SOFC

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ

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Improving La0.6Sr0.4Co0.2Fe0.8O3−δ cathode performance by infiltration of a Sm0.5Sr0.5CoO3−δ coating

Cited by 130 publications

References 18 publications

Structural and electrical properties of Sr(Ti, Fe)O3-δ materials for SOFC cathodes

Structural and electrical properties of Sr(Ti, Fe)O3-δ materials for SOFC cathodes

Electrochemical Behaviors for Ag, LSCF and BSCF as Oxygen Electrodes for Proton Conducting IT-SOFC

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La0.6Sr0.4Co0.2Fe0.8O3-δversus Ba0.5Sr0.5Co0.8Fe0.2O3-δ

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Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δversus Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ