High-Temperature Coulometric Titration of La1−xSrxCoO3−δ: Evidence for the Effect of Electronic Band Structure on Nonstoichiometry Behavior

Lankhorst, Marc M.; Bouwmeester, Henny J.M.; Verweij, H.

doi:10.1006/jssc.1997.7531

Cited by 129 publications

(116 citation statements)

References 23 publications

(25 reference statements)

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“…The nonstoichiometry data from Lankhorst et al, 62 Kawada et al/Mizusaki et al 60,63 and Kuhn et al 64 for bulk samples were numerically evaluated in terms of Eq. 4.…”

Section: Eis -Temperature Dependent Measurements-freshly Deposited Lmentioning

confidence: 99%

The Superior Properties of La_0.6Ba_0.4CoO_3-δThin Film Electrodes for Oxygen Exchange in Comparison to La_0.6Sr_0.4CoO_3-δ

Rupp

Schmid

Nenning

et al. 2016

J. Electrochem. Soc.

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The electrochemical properties of La0.6Ba0.4CoO3-δ (LBC) and La0.6Sr0.4CoO3-δ (LSC) dense thin film model electrodes, deposited by pulsed laser deposition at 600°C on yttria-stabilized zirconia (100) electrolytes, were investigated by electrochemical impedance spectroscopy (EIS) at 450–600°C and 10−4 to 1 bar pO2. This comparative study reveals the influence of the A-site dopant size on the catalytic activity for the oxygen exchange, chemical capacitance and electronic conductivity. For both thin films the overall oxygen reduction is still limited by the oxygen surface exchange, although an extraordinarily high activity for the oxygen reduction reaction (ORR) was measured (LBC ∼0.18 Ωcm²/LSC ∼0.6 Ωcm² at 604°C and 0.21 bar pO2). Moreover, LBC exhibits a rather low activation energy for the ORR (1.19 ± 0.11 eV) together with a high electronic conductivity (839 S·cm−1 at ∼442°C). Based on these excellent electrochemical properties, LBC may also be a highly promising material for porous cathodes in intermediate temperature (400–600°C) solid oxide fuel cells.

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“…The nonstoichiometry data from Lankhorst et al, 62 Kawada et al/Mizusaki et al 60,63 and Kuhn et al 64 for bulk samples were numerically evaluated in terms of Eq. 4.…”

Section: Eis -Temperature Dependent Measurements-freshly Deposited Lmentioning

confidence: 99%

The Superior Properties of La_0.6Ba_0.4CoO_3-δThin Film Electrodes for Oxygen Exchange in Comparison to La_0.6Sr_0.4CoO_3-δ

Rupp

Schmid

Nenning

et al. 2016

J. Electrochem. Soc.

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“…Lattice vacancies are generally determined using redox titrations or thermogravimetric analysis (TGA) [53][54][55][56][57][58][59], but for nanomaterials and materials with very few vacancies, less conventional methods are required such as EXAFS [60,61], XANES [61], other X-ray techniques [53,61], Raman spectroscopy [60,61], high resolution TEM [61], EELS [62], XEDS [63], STEM [64], neutron diffraction [53,59], and a plethora of esoteric techniques [65][66][67][68][69][70][71][72][73].…”

Section: B Lattice Vacanciesmentioning

confidence: 99%

Lattice vacancies responsible for the linear dependence of the low-temperature heat capacity of insulating materials

Schliesser

Woodfield

2015

Phys. Rev. B

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The linear dependence on temperature (γT) of the heat capacity at low temperatures (T < 15 K) is traditionally attributed to conduction electrons in metals; however, many insulators also exhibit a linear dependence that has been attributed to a variety of other physical properties. The property most commonly used to justify the presence of this linear dependence is lattice vacancies, but a correlation between these two properties has never been shown. We have devised a theory that justifies a linear heat capacity as a result of lattice vacancies, and we provide measured values and data from the literature to support our arguments. We postulate that many small Schottky anomalies are produced by a puckering of the lattice around these vacancies, and variations in the lattice caused by position or proximity to some form of structure result in a distribution of Schottky anomalies with different energies. We present a mathematical model to describe these anomalies and their distribution based on literature data that ultimately results in a linear heat capacity. From these calculations, a quantitative relationship between the linear term and the concentration of lattice vacancies is identified, and we verify these calculations using values of γ and vacancy concentrations for several materials. We have compiled many values of γ and vacancy concentrations from the literature which show several significant trends that provide further evidence for our theory.

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“…Based on Faraday's law, this procedure involves fitting C chem vs. P O2 to a nonstoichiometry model (proposed originally by Mizusaki [49] , and later refined by Lankhorst [50] ) that assumes electrons are ideally delocalized. This itinerant electron model has been found to explain the nonstoichiometry properties of LSC over a wide range of T, P O2 , and Sr content [49,51] . The best fit of C chem extracted from Fig.…”

Section: C-4 Linear Responsementioning

confidence: 87%

Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

Adler¹,

Dunyushkina²,

Huff³

et al. 2006

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The goal of this project was to develop an improved understanding of factors governing performance and degradation of mixed-conducting SOFC cathodes. Two new diagnostic tools were developed to help achieve this goal: 1) microelectrode half-cells for improved isolation of cathode impedance on thin electrolytes, and 2) nonlinear electrochemical impedance spectroscopy (NLEIS), a variant of traditional impedance that allows workers to probe nonlinear rates as a function of frequency. After reporting on the development and efficacy of these tools, this document reports on the use of these and other tools to better understand performance and degradation of cathodes based on the mixed conductor La 1-x Sr x CoO 3-δ (LSC) on gadolinia or samaria-doped ceria (GDC or SDC). We describe the use of NLEIS to measure O 2 exchange on thin-film LSC electrodes, and show that O 2 exchange is most likely governed by dissociative adsorption. We also describe parametric studies of porous LSC electrodes using impedance and NLEIS. Our results suggest that O 2 exchange and ion transport co-limit performance under most relevant conditions, but it is O 2 exchange that is most sensitive to processing, and subject to the greatest degradation and sample-to-sample variation. We recommend further work that focuses on electrodes of well-defined or characterized geometry, and probes the details of surface structure, composition, and impurities. Parallel work on primarily electronic conductors (LSM) would also be of benefit to developers, and to improved understanding of surface vs. bulk diffusion.

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High-Temperature Coulometric Titration of La1−xSrxCoO3−δ: Evidence for the Effect of Electronic Band Structure on Nonstoichiometry Behavior

Cited by 129 publications

References 23 publications

The Superior Properties of La_0.6Ba_0.4CoO_3-δThin Film Electrodes for Oxygen Exchange in Comparison to La_0.6Sr_0.4CoO_3-δ

The Superior Properties of La_0.6Ba_0.4CoO_3-δThin Film Electrodes for Oxygen Exchange in Comparison to La_0.6Sr_0.4CoO_3-δ

Lattice vacancies responsible for the linear dependence of the low-temperature heat capacity of insulating materials

Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

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High-Temperature Coulometric Titration of La1−xSrxCoO3−δ: Evidence for the Effect of Electronic Band Structure on Nonstoichiometry Behavior

Cited by 129 publications

References 23 publications

The Superior Properties of La0.6Ba0.4CoO3-δThin Film Electrodes for Oxygen Exchange in Comparison to La0.6Sr0.4CoO3-δ

The Superior Properties of La0.6Ba0.4CoO3-δThin Film Electrodes for Oxygen Exchange in Comparison to La0.6Sr0.4CoO3-δ

Lattice vacancies responsible for the linear dependence of the low-temperature heat capacity of insulating materials

Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

Contact Info

Product

Resources

About

The Superior Properties of La_0.6Ba_0.4CoO_3-δThin Film Electrodes for Oxygen Exchange in Comparison to La_0.6Sr_0.4CoO_3-δ

The Superior Properties of La_0.6Ba_0.4CoO_3-δThin Film Electrodes for Oxygen Exchange in Comparison to La_0.6Sr_0.4CoO_3-δ