Structure and oxygen stoichiometry of SrCo0.8Fe0.2O3−δ and Ba0.5Sr0.5Co0.8Fe0.2O3−δ

McIntosh, Steven; Vente, Jaap F.; Haije, W.G.; Blank, Dave H.A.; Bouwmeester, Henny J.M.

doi:10.1016/j.ssi.2006.03.041

Cited by 194 publications

(147 citation statements)

References 22 publications

Supporting

Mentioning

131

Contrasting

Unclassified

Order By: Relevance

“…At OCV, C chem values for BSCF are much higher than for LSCF: this is in agreement with the BSCF oxygen stoichiometric properties, which make BSCF a material with unusually high oxygen deficiency 23,73 and further confirmed by the TGA and TPR results, as illustrated in the Discussion on redox behavior section. Fig.…”

Section: Resultssupporting

confidence: 81%

See 1 more Smart Citation

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.

View full text Add to dashboard Cite

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...

show abstract

Section: Resultssupporting

confidence: 81%

“…23,73 Moreover, BSCF also has an excellent surface exchange coefficient. All these features support the very good performances obtained in SOFC using BSCF cathodes.…”

Section: Tga and Tpr Results-inmentioning

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.

View full text Add to dashboard Cite

show abstract

“…As discussed earlier, the temperature-profile XRD results for BIO, BIC, BICL025, BICL05, and BIL show phase changes between the ordered brownmillerite and disordered cubic perovskite structures. Based on these results it was expected that the associated characteristic endothermic peaks on heating and exothermic peaks on cooling would be observed in the DSC for reversible order-disorder transition [23,31,32]. The endothermic peak was observed for the BIO sample at 925 • C on heating and the exothermic peak at 1090 • C on cooling, as shown in the DSC in the top right corner of Fig.…”

Section: Thermogravimetric Analysis and Dscmentioning

confidence: 78%

Preparation and characterization of Ce- and La-doped Ba2In2O5 as candidates for intermediate temperature (100–500°C) solid proton conductors

Janković

Wilkinson

Hui

2012

Journal of Power Sources

View full text Add to dashboard Cite

a b s t r a c tFive different compositions of brownmillerite materials, Ce-and La-doped, and undoped Ba 2 In 2 O 5 were synthesized via the solid-state reaction and the glycine-nitrate combustion process. Properties of the materials were characterized using XRD, HR-TEM, and TGA/DSC techniques. Conductivity measurements by AC impedance spectroscopy, performed in air and hydrogen-containing atmospheres, in the temperature range from 100• C to 500• C, were correlated to the properties of the materials and revealed the effects of dopant, microstructure, temperature and atmosphere on the total electrical conductivity of the materials. All compositions showed low conductivity in air. In hydrogen-containing atmospheres, while Ce-and La-doped Ba 2 In 2 O 5 showed low conductivity (4 × 10 −6 -3 × 10 −6 S cm −1 at 500 • C), undoped Ba 2 In 2 O 5 demonstrated a surprisingly high conductivity (between 0.02 S cm −1 and 0.7 S cm −1 in the temperature range from 300• C to 500• C), especially samples produced by the glycine-nitrate process. This finding creates potential opportunity for using Ba 2 In 2 O 5 as a proton-conductive material in intermediate temperature fuel cells.

show abstract

“…For the Ba/Sr=1 samples, the transition temperature is between 450 and 550°C. The observed transitions from semi-conductivity to metal-like conductivity are not due to a phase transition, as the phase stability was investigated by previous in situ high-temperature XRD characterizations of the same material, i.e., Ba 0:5 Sr 0:5 Co 0:8 Fe 0:2 O 3Àd , and the cubic phase was found in the temperature regime from room temperature to 1,000°C in air [21,30,31].…”

Section: Electrical Conductivitymentioning

confidence: 92%

Electrical conductivity and defect chemistry of $$ {\hbox{B}}{{\hbox{a}}_x}{\hbox{S}}{{\hbox{r}}_{{1} - x}}{\hbox{C}}{{\hbox{o}}_y}{\hbox{F}}{{\hbox{e}}_{{1} - y}}{{\hbox{O}}_{{3} - \delta }} $$ perovskites

Yáng

Harvey

Infortuna

et al. 2010

J Solid State Electrochem

View full text Add to dashboard Cite

Bulk Ba x Sr 1Àx Co y Fe 1Ày O 3Àd compositions (BSCF) were synthesized by the solid-state reaction method. The electrical conductivity of ceramic bars was measured using a dc four-probe method as a function of temperature in air up to 970°C. All compositions showed thermally activated p-type semi-conductivity up to~450°C and then a transition to metal-like conductivity. The smallpolaron hopping p-type semi-conductivity depends on the oxygen nonstoichiometry, which increases with increasing temperature. Metal-like conductivity is attributed to the overlap of the transition metal d-electron orbitals with the oxygen p-orbitals. Strontium-rich compositions show higher conductivity. The Co/Fe ratio does not influence much the p-type semi-conduction. Iron-rich compositions revealed more metal-like conduction behavior. The degree of overlap between transition metal d-orbitals and oxygen p-orbitals depends on the Ba/Sr as well as on the Co/Fe ratios.

show abstract

Structure and oxygen stoichiometry of SrCo0.8Fe0.2O3−δ and Ba0.5Sr0.5Co0.8Fe0.2O3−δ

Cited by 194 publications

References 22 publications

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

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

Preparation and characterization of Ce- and La-doped Ba2In2O5 as candidates for intermediate temperature (100–500°C) solid proton conductors

Electrical conductivity and defect chemistry of $$ {\hbox{B}}{{\hbox{a}}_x}{\hbox{S}}{{\hbox{r}}_{{1} - x}}{\hbox{C}}{{\hbox{o}}_y}{\hbox{F}}{{\hbox{e}}_{{1} - y}}{{\hbox{O}}_{{3} - \delta }} $$ perovskites

Contact Info

Product

Resources

About

Structure and oxygen stoichiometry of SrCo0.8Fe0.2O3−δ and Ba0.5Sr0.5Co0.8Fe0.2O3−δ

Cited by 194 publications

References 22 publications

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

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

Preparation and characterization of Ce- and La-doped Ba2In2O5 as candidates for intermediate temperature (100–500°C) solid proton conductors

Electrical conductivity and defect chemistry of $$ {\hbox{B}}{{\hbox{a}}_x}{\hbox{S}}{{\hbox{r}}_{{1} - x}}{\hbox{C}}{{\hbox{o}}_y}{\hbox{F}}{{\hbox{e}}_{{1} - y}}{{\hbox{O}}_{{3} - \delta }} $$ perovskites

Contact Info

Product

Resources

About

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

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