Modeling of electrical conductivity in the proton conductor Ba0.85K0.15ZrO3−δ

Sherafat, Z.; Paydar, Mohammad Hossein; Antunes, I.; Nasani, Narendar; Brandão, Ana D.; Fagg, Duncan P.

doi:10.1016/j.electacta.2015.03.018

Cited by 34 publications

(4 citation statements)

References 31 publications

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“…As also observed in the previously studied Ba(Zr 0.7 Ce 0.2 ) 1−-(x/0.9) Pr x Y 0.1 O 3−δ system, 15 the conductivities in dry air and N 2 become closer at low temperature, suggesting that this is a common feature of such perovskites. The trend toward convergence in the BZCY72 end-member and Pr-lean phases in the two atmospheres at low temperature may be attributable to the higher activation energy of electron−hole conductivity with respect to oxide-ion conductivity 43,44 such that the ionic contribution to conductivity is higher at low rather than high temperatures. This has the effect that the conductivity is less affected by the oxygen activity of different atmospheres at lower temperature.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr_0.7Ce_0.2Y_0.1O_3−δ

et al. 2018

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The BaZr0.7Ce0.2Y0.1O3--BaPrO3- perovskite system, of interest for high-temperature electrochemical applications involving mixed protonic-electronic conductivity, forms a solid solution with a wide interval of Ba substoichiometry in the range Ba(Ce0.2Zr0.7)1-xPrxY0.1O3-, 0 ≤ x ≤ 1. Structural phase transitions mapped as a function of temperature and composition by high-resolution neutron powder diffraction and synchrotron X-ray diffraction reveal higher symmetry for lower Pr content and higher temperatures, with the largest stability field observed for rhombohedral symmetry (space group, 3 ̅). Rietveld refinement, supported by magnetic-susceptibility measurements, indicates that partitioning of the B-site cations over the A and B perovskite sites compensates Ba substoichiometry in preference to A-site vacancy formation and that multiple cations are distributed over both sites. Electron-hole transport dominates electrical conductivity in both wet and dry oxidising conditions, with total conductivity reaching a value of ~ 0.5 S.cm-1 for the x = 1 end-member in dry air at 1173 K. Higher electrical conductivity and the displacement of oxygen loss to higher temperatures with increasing Pr content both reflect the role of Pr in promoting hole formation at the expense of oxygen vacancies. In more reducing conditions (N2) and at low Pr contents, conductivity is higher in humidified atmospheres (~ 0.023 atm pH2O) indicating a protonic contribution to transport, whereas the greater electron-hole conductivity with increasing Pr content results in lower conductivity in humidified N2 due to the creation of protonic defects and the consumption of holes.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr_0.7Ce_0.2Y_0.1O_3−δ

et al. 2018

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“…The calculated values stay in agreement with the literature data. The activation energy of proton conductivity is reported to be 0.5-0.6 eV [26,27], and for oxide ion conductivity, the activation energy is about 0.75-0.8 eV [23]. The effect of materials' microstructure is reflected in the values of E a .…”

Section: Electrical Propertiesmentioning

confidence: 91%

Effect of microstructure on chemical stability and electrical properties of BaCe0.9Y0.1O3 − δ

Łącz

2016

Ionics

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Y-doped barium cerate BaCe 0.9 Y 0.1 O 3 − δ was synthesised by a solid-state reaction method. Materials with different average grain sizes and grain boundary surface areas were obtained. The effect of microstructure on the chemical stability in the CO 2 and H 2 O-containing atmosphere and electrical properties was analysed and discussed. To evaluate the chemical stability of BaCe 0.9 Y 0.1 O 3 − δ , the exposure test was performed. Samples were exposed to the carbon dioxide and water vapour-rich atmosphere at 25°C for 700 h. Thermogravimetry supplied by mass spectrometry was applied to analyse the samples before and after this comprehensive test. The mass loss for samples before and after the test and the amount of BaCO 3 formed during the test were directly treated as the measure of chemical instability of BaCe 0.9 Y 0.1 O 3 − δ in the atmosphere rich in carbon dioxide and water vapour. As it was observed, the BaCe 0.9 Y 0.1 O 3 − δ chemical stability towards CO 2 and H 2 O is not affected by the materials' microstructure. Electrical properties of BaCe 0.9 Y 0.1 O 3 − δ which differs with microstructure were determined using electrochemical impedance spectroscopy (EIS). It was found that the grain interior resistivity and activation energy of grain interior conductivity is microstructure independent. However, the effect on microstructure was seen on the EIS spectra in the range of grain boundary contribution. Therefore, the lowest activation energy and the highest conductivity were observed for a material with the lowest grain boundary surface area.

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“…[ 41 ] For Ba 0.85 K 0.15 ZrO 3–δ , proton conduction was dominant in the temperature range of 550–700 °C in wet N 2 , while a conduction transition from proton to hole conduction was observed in wet oxidative atmospheres. [ 62 ] Simultaneously, a shift from hole‐dominated to proton‐dominated conduction was observed by increasing p H2O . In addition, proton conduction can convert to O 2− conduction with increasing temperature, owing to the dehydration reaction and sufficient energy for activating O 2− conduction.…”

Section: Fundamentals Of Proton‐conductive Oxidesmentioning

confidence: 97%

Advanced Cathode Materials for Protonic Ceramic Fuel Cells: Recent Progress and Future Perspectives

Wang

Tang

et al. 2022

Advanced Energy Materials

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Intermediate‐temperature proton ceramic fuel cells (PCFCs)–a promising power generation technology–have attracted significant attention in recent years because of their unique advantages over conventional high‐temperature solid oxide fuel cells and low‐temperature proton exchange membrane fuel cells. The cathodes of PCFCs simultaneously require efficient channels for proton, oxide‐ion, and electron transfer; therefore, designing and engineering cathode materials with tailorable H+, O2−, and e− conductivities are crucial for improving PCFC performance. Despite significant efforts and critical progress in this field, exploring the desired cathode materials remains challenging. This review provides a comprehensive and critical overview of oxide materials for PCFC cathodes, particularly triple H+/O2−/e− conductors. Their proton uptake, conduction mechanisms, and structure–property relationships are focused on to guide future material design. In addition, the electrochemical performance of these cathode materials in PCFCs is discussed and the electrochemical performance gaps among PCFCs with different types of cathode materials are defined. Finally, perspectives on the development of high‐performance PCFCs are proposed.

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Modeling of electrical conductivity in the proton conductor Ba0.85K0.15ZrO3−δ

Cited by 34 publications

References 31 publications

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr_0.7Ce_0.2Y_0.1O_3−δ

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr_0.7Ce_0.2Y_0.1O_3−δ

Effect of microstructure on chemical stability and electrical properties of BaCe0.9Y0.1O3 − δ

Advanced Cathode Materials for Protonic Ceramic Fuel Cells: Recent Progress and Future Perspectives

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Modeling of electrical conductivity in the proton conductor Ba0.85K0.15ZrO3−δ

Cited by 34 publications

References 31 publications

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr0.7Ce0.2Y0.1O3−δ

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr0.7Ce0.2Y0.1O3−δ

Effect of microstructure on chemical stability and electrical properties of BaCe0.9Y0.1O3 − δ

Advanced Cathode Materials for Protonic Ceramic Fuel Cells: Recent Progress and Future Perspectives

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Product

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Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr_0.7Ce_0.2Y_0.1O_3−δ

Structures, Phase Fields, and Mixed Protonic–Electronic Conductivity of Ba-Deficient, Pr-Substituted BaZr_0.7Ce_0.2Y_0.1O_3−δ