La/Ba-based cobaltites as IT-SOFC cathodes: a discussion about the effect of crystal structure and microstructure on the O 2 -reduction reaction

Garcés, Diana; Soldati, Analía Leticia; Troiani, Horacio Esteban; Montenegro-Hernández, Alejandra; Caneiro, A.; Mogni, L.

doi:10.1016/j.electacta.2016.08.132

Cited by 28 publications

(19 citation statements)

References 63 publications

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“…A-site cation ordering in LaBaCo 2 O 5+δ leads to higher performance [30] due to the higher oxygen vacancy concentration as shown in Figure 10a. The higher oxygen vacancy concentration and therefore higher degree of protonation could rationalize the higher performance of LaBaCo 2 O 5+δ compared to La 0.5 Ba 0.5 CoO 3−δ Furthermore, both LaBaCo 2 O 5+δ and La 0.5 Ba 0.5 CoO 3−δ as well as BCFZY have been shown to be very good oxide ion conductors [26,27,28,46].…”

Section: Discussionmentioning

confidence: 99%

“…Both the ordered and disordered variants demonstrate low polarization resistances at temperatures as low as 600 °C (<0.2 Ω·cm 2 ) due to the excellent mixed conducting (electron hole and oxide-ion) nature of the material. In addition, Garces et al have studied the influence of the A-site cation ordering on the mixed electronic and oxide-ion conducting properties in this system [29,30]. They obtained a noticeable improvement of performance with A-site cation ordering (0.35 Ω·cm 2 for La 0.5 Ba 0.5 CoO 3−δ vs. 0.12 Ω·cm 2 for LaBaCo 2 O 5+δ at 600 °C in air).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

et al. 2018

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The effect of A-site cation ordering on the cathode performance and chemical stability of A-site cation ordered LaBaCo2O5+δ and disordered La0.5Ba0.5CoO3−δ materials are reported. Symmetric half-cells with a proton-conducting BaZr0.9Y0.1O3−δ electrolyte were prepared by ceramic processing, and good chemical compatibility of the materials was demonstrated. Both A-site ordered LaBaCo2O5+δ and A-site disordered La0.5Ba0.5CoO3−δ yield excellent cathode performance with Area Specific Resistances as low as 7.4 and 11.5 Ω·cm2 at 400 °C and 0.16 and 0.32 Ω·cm2 at 600 °C in 3% humidified synthetic air respectively. The oxygen vacancy concentration, electrical conductivity, basicity of cations and crystal structure were evaluated to rationalize the electrochemical performance of the two materials. The combination of high-basicity elements and high electrical conductivity as well as sufficient oxygen vacancy concentration explains the excellent performance of both LaBaCo2O5+δ and La0.5Ba0.5CoO3−δ materials at high temperatures. At lower temperatures, oxygen-deficiency in both materials is greatly reduced, leading to decreased performance despite the high basicity and electrical conductivity. A-site cation ordering leads to a higher oxygen vacancy concentration, which explains the better performance of LaBaCo2O5+δ. Finally, the more pronounced oxygen deficiency of the cation ordered polymorph and the lower chemical stability at reducing conditions were confirmed by coulometric titration.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

et al. 2018

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“…The perovskite-type oxide La 0.5 Ba 0.5 CoO 3-δ was first prepared in 1979 [1,2]. By a number of techniques it was shown to have cubic crystal structure with Pm3m space group (S. G.), at least when synthesized in air atmosphere with oxygen partial pressure, pO 2 , ≥ 0.21 atm [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, annealing of La 0.5 Ba 0.5 CoO 3-δ at 900-1200 °C under reducing conditions led to the formation of the double perovskite LaBaCo 2 O 6-δ [3,5,[10][11][12][13][14][15][20][21][22][23]. Thus, according to the results of studying the ordering-disordering phenomenon in LaBaCo 2 O 6-δ -La 0.5 Ba 0.5 CoO 3-δ system [23], the stability field of cubic perovskite at 1000-1100 °C corresponds to the pO 2 range -1.3 ≤ log (pO 2 / atm) ≤ -0.68.…”

Section: Introductionmentioning

confidence: 99%

Oxygen content and defect structure of the perovskite La_0.5Ba_0.5CoO_3–δ

2018

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Perovskite-type complex oxide La0.5Ba0.5CoO3–δ, promising cathode material for solid oxide fuel cells and precursor for synthesis of double perovskite LaBaCo2O6–δ, was prepared as a single-phase material. Its oxygen content was measured by two independent techniques in the temperature range 1000–1100 °C and at oxygen partial pressures corresponding to the stability field of cubic phase. The defect chemistry of this material was studied using the measured δ=f(pO2,T) dependences. The defect structure model based on the localized nature of the electronic defects was proposed and successfully verified.

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“…The choice of three R/CPE elements mirrors the fundamental description of the way a MIEC cathode works, by assuming the three rate-determining steps which summarized by Fukunaga et al [8] in the overall oxygen reduction reaction. [40,41]. Furthermore, it is noted that the fitted capacitance for HF and MF is relatively large compared with the values reported for other cathodes.…”

Section: Comentioning

confidence: 77%

Investigation of La1−Sm−Sr CoO3−δ cathode for intermediate temperature solid oxide fuel cells

Chen

et al. 2017

Journal of Power Sources

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La 1-x Sm x-y Sr y CoO 3-G (LSSC; x=0.475, 0.650, 0.825, y=0.35, 0.40, 0.45) compounds, which have the same compositions as the La 0.7 Sr 0.3 CoO 3-G (LSC) and Sm 0.5 Sr 0.5 CoO 3-G (SSC) mixture (corresponding mole ratio is 3:1, 1:1 and 1:3, respectively), are synthesized through a conventional solid-state reaction and characterized by X-ray diffraction, thermal expansion coefficient, X-ray photoelectron spectrometer and electrical conductivity measurement, as well as the electrochemical impedance spectra and single cell performance measurement. Interestingly, the experimental results reveal that with the linear increase of y in LSSC, the conductivity of the corresponding samples does not alter linearly but reaches a peak when y=0.35, namely, the maximum electrical conductivity enhancing from 2148 S cm-1 (LSC, y=0.30) and 1802 S cm-1 (SSC, y=0.50) to 2750 S cm-1 (y=0.35). In addition, this turning point coincidently corresponds to the structure transition from hexagonal (y=0.35) to orthorhombic (y=0.40). Furthermore, comparing with LSC and SSC, the cathode polarization resistance (R P) decreases by about 50% and 38%, respectively, after employing the LSSC (y=0.40) compound as cathode at 800 o C and 0.21 atm p(O 2), which also leads to an increment

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La/Ba-based cobaltites as IT-SOFC cathodes: a discussion about the effect of crystal structure and microstructure on the O 2 -reduction reaction

Cited by 28 publications

References 63 publications

Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

Oxygen content and defect structure of the perovskite La_0.5Ba_0.5CoO_3–δ

Investigation of La1−Sm−Sr CoO3−δ cathode for intermediate temperature solid oxide fuel cells

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La/Ba-based cobaltites as IT-SOFC cathodes: a discussion about the effect of crystal structure and microstructure on the O 2 -reduction reaction

Cited by 28 publications

References 63 publications

Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

Oxygen content and defect structure of the perovskite La0.5Ba0.5CoO3–δ

Investigation of La1−Sm−Sr CoO3−δ cathode for intermediate temperature solid oxide fuel cells

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Oxygen content and defect structure of the perovskite La_0.5Ba_0.5CoO_3–δ