Comparative Studies of SrCo1−xTaxO3−δ (x=0.05–0.4) Oxides as Cathodes for Low‐Temperature Solid‐Oxide Fuel Cells

Li, Mengran; Zhou, Wei; Zhu, Zhonghua

doi:10.1002/celc.201500157

Cited by 55 publications

(51 citation statements)

References 42 publications

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“…[46][47] About~0.115 g of powder sample, dissolved in 4.0 M HCl solution in an argon atmosphere, was titrated against~0.1 M aqueous solution of sodium thiosulphate. [46][47] About~0.115 g of powder sample, dissolved in 4.0 M HCl solution in an argon atmosphere, was titrated against~0.1 M aqueous solution of sodium thiosulphate.…”

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

“…[46] The surface morphology and cross-sectional interface microstructures of cells were studied by scanning electron microscopy (SEM; JEOL 6610) at 15 kV applied potential. The m o , m T and δ T are the initial mass, mass at temperature 'T' (measured by TGA results) and oxygen vacancy concentration at target temperature T, respectively.…”

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

“…The room temperature oxygen non-stoichiometry and average oxidation state of Fe in SLFNTx (x = 0-0.1) oxides were estimated by iodometric titration. [46][47] About~0.115 g of powder sample, dissolved in 4.0 M HCl solution in an argon atmosphere, was titrated against~0.1 M aqueous solution of sodium thiosulphate. The starch solution was used to confirm the complete titration i. e. colour changes from reddish-brown to light yellow.…”

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

“…The m o , m T and δ T are the initial mass, mass at temperature 'T' (measured by TGA results) and oxygen vacancy concentration at target temperature T, respectively. [46] The surface morphology and cross-sectional interface microstructures of cells were studied by scanning electron microscopy (SEM; JEOL 6610) at 15 kV applied potential. X-ray photoelectron spectroscopy (XPS) scans were carried out on Kratos Axis Ultra spectrometric with Al Kα (1,486.8 eV) radiation source at 150 W. The deconvolution of XPS data were analysed via CasaXPS program with a Shirley background subtraction method.…”

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

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Unveiling Lithium Roles in Cobalt‐Free Cathodes for Efficient Oxygen Reduction Reaction below 600 °C

Rehman

Knibbe

et al. 2019

ChemElectroChem

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Improving the sluggish electrocatalytic oxygen reduction reaction (ORR) over cobalt-free cathodes at 550-800°C is imperative to circumvent challenges faced by practical operation of intermediate temperature solid oxide fuel cells. In this work, we synthesize novel cobalt-free, lithium (Li)-doped, perovskite oxides Sr 1-x Li x Fe 0.8 Nb 0.1 Ta 0.1 O 3-δ (SLFNTx, x = 0-0.1) as cathodes for efficient ORR catalysis. When the Li concentration is less than 0.05, ORR activity is enhanced by over 1.6-fold in comparison to the undoped SFNT below 600°C in both symmetrical and anode-supported single cells configurations. Our comprehensive investigation over crystal structure, surface, and mixed conductivities revealed that a moderate concentration (< 0.05) of Li could bestow the perovskite with a stable cubic perovskite structure that contains an optimal concentration of oxygen vacancies and A-site deficiencies. Such trend originates from the lower electronegativity and smaller size of Li dopant than the strontium host. The lower electronegativity increases oxygen vacancies. The small Li dopant induces thermal-migration of Li species and creates A-site deficiency. These insights highlight an effective strategy to advance the performance of cobalt-free ORR electrocatalyst below 600°C through in situ thermal surface migration of the A-site cations.

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Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

Section: Oxygen Non-stoichiometry Measurementsmentioning

confidence: 99%

See 2 more Smart Citations

Unveiling Lithium Roles in Cobalt‐Free Cathodes for Efficient Oxygen Reduction Reaction below 600 °C

Rehman

Knibbe

et al. 2019

ChemElectroChem

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“…High valence cations with good solid solubility are also found effective in improving structure SrCoO3-δ at room temperature may be influenced by their substitution level 202,203,206,213 : tetragonal structure (P4/mmm) is obtained if the doping content lower than 10 mol %; higher doping level will lead to the cubic perovskite structure. …”

Section: Fixed Valence Dopantsmentioning

confidence: 99%

Development of cathode materials for intermediate temperature solid oxide fuel cells

Li¹

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A solid oxide fuel cell (SOFC) is a promising energy device that can generate electricity by converting chemical energy of nearly all types of fuels with very high efficiency. However, its high operating temperature (> 850°C) is the main impediment to deploying this technology, because high temperature can lead to sealing issues, slow start-up/shut-down procedures, poor thermal cycling stability, poor fuel cell durability, as well as high material and operational cost. Lowering the operating temperature down to intermediate temperature (IT, is an effective and significant strategy to solve these issues, but it makes the kinetics of electrolyte and electrodes especially the cathode sluggish. Despite slow kinetics of electrolyte have been significantly alleviated by using novel electrolyte materials and thin film fabrication technology, low electroactivity of IT-SOFC cathode still remains a major challenge. Besides, the susceptibility of cathodes containing alkaline-earth elements to CO2 is another concern on long-term cathode stability, especially at low temperature. Therefore, developing a robust cathode material with high electroactivity is significant for commercialising SOFC technology, and have received growing research interest and efforts in recent years.This thesis is mainly focused on developing highly active and stable cathode materials based on SrCoO3-δ perovskite oxide for IT-SOFC. The factors affecting catalysis on oxygen reduction reaction (ORR), and the CO2-poisoning mechanisms on the SrCoO3-δ-based cathodes at intermediate temperature were investigated. In this thesis, we developed and evaluated SrCoO3-δ doped with highvalence elements such as P, Nb, and Ta as cathodes for SOFC by studying their crystal structures, compositions, microstructures and electrochemical properties as well as electroactivity in ORR at intermediate temperature.In the first part of the experimental chapters, we mainly worked on developing SrCoO3-δ-based cathode materials and studying the effects of high fixed valence dopants (P, Ta, and Nb) on SrCoO3-δ perovskite cathode for IT-SOFC. We successfully doped P and Ta into SrCoO3-δ oxide separately, and found these dopants at certain doping level can stabilise the beneficial perovskite structure at both room temperature and intermediate temperature. The study on P-doped SrCoO3-δ reveals that the stabilising effect of P is a result of the high-valence that prevents oxygen vacancy ordering and phase distortions. The electrical conductivity of SrCoO3-δ can be enhanced by small amount of P or Ta (≤ 5 mol%) due to the stabilized perovskite structure and high valence of P and Ta, but can be adversely affected for higher doping level as shown in study on SrCo1-xTaxO3-δ. Additionally, SrCoO3-δ doped with <20 mol% Ta shows superior electroactivity on ORR at IT, with a cathode polarisation resistance as low as 0.089~0.11 Ω·cm 2 at 550°C for SrCo0.95Ta0.05O3-δ. However, the high fixed valence can II decrease oxygen vacancy content, so high doping level (e.g. 40mol%) of Ta can ser...

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Cathodes for Solid Oxide Fuel Cell

Zhou

Jin

2020

Solid Oxide Fuel Cells

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Comparative Studies of SrCo_1−xTa_xO_3−δ (x=0.05–0.4) Oxides as Cathodes for Low‐Temperature Solid‐Oxide Fuel Cells

Cited by 55 publications

References 42 publications

Unveiling Lithium Roles in Cobalt‐Free Cathodes for Efficient Oxygen Reduction Reaction below 600 °C

Unveiling Lithium Roles in Cobalt‐Free Cathodes for Efficient Oxygen Reduction Reaction below 600 °C

Development of cathode materials for intermediate temperature solid oxide fuel cells

Cathodes for Solid Oxide Fuel Cell

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