Oxygen isotope exchange with a dense La0.6Sr0.4CoO3âÎ´ electrode on a Ce0.9Ca0.1O1.9 electrolyte

Kawada, Tatsuya; Masuda, Koichi; Suzuki, Junji; Kaimai, Atsushi; Kawamura, Ken; Nigara, Yutaka; Mizusaki, Junichiro; Yugami, Hiroo; Arashi, H.; Sakai, Natsuko; Yokokawa, Harumi

doi:10.1016/s0167-2738(99)00046-6

Cited by 107 publications

(34 citation statements)

References 7 publications

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“…When the electrode oxide is highly nonstoichiometric with large amount of defects on oxygen sublattice, the bulk diffusion through the electrode is the predominant reaction path. Typical examples are La 1¹x Sr x CoO 3¹D 38,40,50,64,68 in oxidizing atmospheres and doped CeO 2 55 in reduced atmospheres.…”

Section: Surface Reaction (Dissociative Adsorption)-electrode Bulkmentioning

confidence: 99%

Model for Solid Electrolyte Gas Electrode Reaction Kinetics; Key Concepts, Basic Model Construction, Extension of Models, New Experimental Techniques for Model Confirmation, and Future Prospects

Mizusaki

2014

Electrochemistry

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In order to survey history and state of art of theoretical and kinetic studies of gas electrode reaction on solid oxide electrolyte, overview was made on the research works reported by the author and his co-investigators. Through reviewing their works, frontier of research is clarified. It was shown that electrode reaction is controlled by nonfaradaic chemical reaction process, and the nature of the overpotential is the chemical potential deviation of the interface from equilibrium state. Mechanical stress at the electrode/solid electrolyte interface is considered varying with the overpotential. Importance is emphasized for mechano-electrochemistry, the field to study the relationship of electrochemistry and mechanical property of the electrochemical cells.

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Section: Surface Reaction (Dissociative Adsorption)-electrode Bulkmentioning

confidence: 99%

Model for Solid Electrolyte Gas Electrode Reaction Kinetics; Key Concepts, Basic Model Construction, Extension of Models, New Experimental Techniques for Model Confirmation, and Future Prospects

Mizusaki

2014

Electrochemistry

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“…12,19,20 Studies of the dc current voltage characteristics, however, are rather scarce on thin mixed ionic electronic conducting (MIEC) thin films, since determination of the true electrode overpotential (voltage loss at the working electrode) is often difficult in solid-state ionics. 31,56,57 Two experimental approaches exist: Manufacturing sufficiently small working electrodes (microelectrodes) in order to ensure that the polarization resistance of the counter electrode is much smaller than that of the working electrode and can therefore be neglected. 17,25,45 However, in previous experiments we found that the resistance of La 0.6 Sr 0.4 FeO 3−δ (LSF) thin films can irreversibly increase by a factor of 10–100 during the photolithographic microstructuring step.…”

Section: Introductionmentioning

confidence: 99%

How To Get Mechanistic Information from Partial Pressure-Dependent Current–Voltage Measurements of Oxygen Exchange on Mixed Conducting Electrodes

2018

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The oxygen incorporation and evolution reaction on mixed conducting electrodes of solid oxide fuel or electrolysis cells involves gas molecules as well as ionic and electronic point defects in the electrode. The defect concentrations depend on the gas phase and can be modified by the overpotential. These interrelationships make a mechanistic analysis of partial pressure-dependent current–voltage experiments challenging. In this contribution it is described how to exploit this complex situation to unravel the kinetic roles of surface adsorbates and electrode point defects. Essential is a counterbalancing of oxygen partial pressure and dc electrode polarization such that the point defect concentrations in the electrode remain constant despite varying the oxygen partial pressure. It is exemplarily shown for La0.6Sr0.4FeO3−δ (LSF) thin film electrodes on yttria-stabilized zirconia how mechanistically relevant reaction orders can be obtained from current–voltage curves, measured in a three-electrode setup. This analysis strongly suggests electron holes as the limiting defect species for the oxygen evolution on LSF and reveals the dependence of the oxygen incorporation rate on the oxygen vacancy concentration. A virtual independence of the reaction rate from the oxygen partial pressure was empirically found for moderate oxygen pressures. This effect, however, arises from a counterbalancing of defect and adsorbate concentration changes.

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“…The ORR activities of La 1-x Sr x CoO 3-δ P films (x = 0.2 and 0. , red = Co-stoichiometric, orange = most active Co-deficient P. References: Wang et al, 34 Yang et al, 35 Kawada et al, 36 Crumlin et al (15 nm R with y = 0.5 -assumed to be a dense layer -deposited on P with x = 0.2, 5 0.4 6 ), Sase et al, 3 Ma et al 8 (transformed from ASR to k q using Eq. 3), Lee et al 7,37 of these two-phase films are given.…”

Section: Activity Of Satp Films and Films Containing Metastable Phases-mentioning

confidence: 99%

Oxygen Exchange Activity of La-Sr-Co-O PLD Films and Quantification of (La,Sr)CoO_3-_δ/(La,Sr)₂CoO₄₊_δ/O₂Triple Phase Boundary Activity

Stämmler

Merkle

Maier

2017

J. Electrochem. Soc.

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Thin compact La-Sr-Co-O composite films consisting of (La,Sr)CoO 3-δ and (La,Sr) 2 CoO 4+δ crystallites were prepared by compositional phase separation during pulsed laser deposition. While the total La:Sr ratio is kept constant at 70:30, different phase ratios and crystallite sizes are investigated. The effect of hetero-interfaces on the oxygen reduction reaction (ORR) kinetics was investigated by impedance spectroscopy. The enhancement relative to the appropriate reference activity is quantified in terms of the triple phase boundary (TPB) length specific activity k TPB , resulting in k TPB = 2-9 · 10 −13 cm 2 /s at 600 • C. A metastable Co-deficient perovskite phase La 0.7 Sr 0.3 Co 0.9 O 3-δ formed in La-Sr-Co-O films under certain conditions was found to be highly active with an effective rate constant k q = 3 · 10 −6 cm/s at 600 • C, representing one possible source for the activity enhancement in these composite films. (La,Sr)CoO 3-δ /(La,Sr) 2 CoO 4±δ (perovskite phase, P/RuddlesdenPopper phase, R) two-phase materials were reported in literature to show enhanced activity for the oxygen reduction reaction (ORR) compared to reference single-phase samples 1-11 making them a promising new material for highly active cathodes in intermediate temperature solid oxide fuel cells. This enhancement was attributed to effects at the P/R/O 2 triple phase boundary (TPB). It is important to note that -in contrast to the traditional use -here TPB does not refer to the contact of gas phase, electrode and electrolyte material, but to locations where hetero-grain boundaries of two components of the cathode material are exposed to the atmosphere. The literature approaches to investigate this ORR enhancement at P/R hetero-interfaces (additional ORR activity related to TPBs, which in this work is simply denoted as "TPB effect") can be roughly divided into local ORR activity measurements by 18 O exchange and SIMS experiments, 1-4 and integral activity measurements of macroscopic two-phase electrodes with high TPB density by impedance spectroscopy. 5-11With a local measurement, the activity of the surface at a single TPB as well as that at neighboring P and R phases (reference activities) can be determined. If sufficiently high lateral resolution and vertical sampling depth is available, the strength of the TPB effect can be quantified in terms of a TPB length specific contribution to the activity. With an integral measurement of a whole electrode which contains a large amount of P and R grains and TPBs, an average activity is measured with contributions from the grains (surfaces with effective rate constants k P (x) in P La 1-x Sr x CoO 3-δ with Sr fraction x and k R (y) in R (La 1-y Sr y ) 2 CoO 4±δ with Sr fraction y) and from TPBs, which has to be compared to an appropriate reference activity and related to the TPB density for quantification.In literature, local activity measurements were performed either on ceramic samples where P/R hetero-interfaces formed sporadically by spontaneous phase separation, 1,3 or as illustrated ...

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Oxygen isotope exchange with a dense La0.6Sr0.4CoO3âÎ´ electrode on a Ce0.9Ca0.1O1.9 electrolyte

Cited by 107 publications

References 7 publications

Model for Solid Electrolyte Gas Electrode Reaction Kinetics; Key Concepts, Basic Model Construction, Extension of Models, New Experimental Techniques for Model Confirmation, and Future Prospects

Model for Solid Electrolyte Gas Electrode Reaction Kinetics; Key Concepts, Basic Model Construction, Extension of Models, New Experimental Techniques for Model Confirmation, and Future Prospects

How To Get Mechanistic Information from Partial Pressure-Dependent Current–Voltage Measurements of Oxygen Exchange on Mixed Conducting Electrodes

Oxygen Exchange Activity of La-Sr-Co-O PLD Films and Quantification of (La,Sr)CoO_3-_δ/(La,Sr)₂CoO₄₊_δ/O₂Triple Phase Boundary Activity

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Oxygen isotope exchange with a dense La0.6Sr0.4CoO3âÎ´ electrode on a Ce0.9Ca0.1O1.9 electrolyte

Cited by 107 publications

References 7 publications

Model for Solid Electrolyte Gas Electrode Reaction Kinetics; Key Concepts, Basic Model Construction, Extension of Models, New Experimental Techniques for Model Confirmation, and Future Prospects

Model for Solid Electrolyte Gas Electrode Reaction Kinetics; Key Concepts, Basic Model Construction, Extension of Models, New Experimental Techniques for Model Confirmation, and Future Prospects

How To Get Mechanistic Information from Partial Pressure-Dependent Current–Voltage Measurements of Oxygen Exchange on Mixed Conducting Electrodes

Oxygen Exchange Activity of La-Sr-Co-O PLD Films and Quantification of (La,Sr)CoO3-δ/(La,Sr)2CoO4+δ/O2Triple Phase Boundary Activity

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Oxygen isotope exchange with a dense La0.6Sr0.4CoO3âÎ´ electrode on a Ce0.9Ca0.1O1.9 electrolyte

Oxygen Exchange Activity of La-Sr-Co-O PLD Films and Quantification of (La,Sr)CoO_3-_δ/(La,Sr)₂CoO₄₊_δ/O₂Triple Phase Boundary Activity