Evaluation of polymorphism and charge transport in a BaO-CaO-Ta2O5 perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy

Kalpana Singh; Hua Yang; Zheyu Zhang; Maxim Avdeev; Ashfia Huq; Dong Ying Wu; Jey Jau Lee; Wang Hay Kan; Venkataraman Thangadurai

doi:10.1039/d2ta02725a

Evaluation of polymorphism and charge transport in a BaO-CaO-Ta₂O₅ perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy

Kalpana Singh, Hua Yang, Zheyu Zhang, Maxim Avdeev, Ashfia Huq, Dong Ying Wu, Jey Jau Lee, Wang Hay Kan^*, Venkataraman Thangadurai^*

^*Corresponding author for this work

School of Chemistry

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

Among the alkaline earth-based perovskite oxides, the Ba-based perovskites have superior chemical stability and tunable electrical/catalytic property via chemical substitution/doping. One of the best-known examples is Ba₃Ca_1.18Nb_1.82O_8.73 as a ceramic proton conductor for all-solid-state steam electrolysis and solid oxide fuel cells (SOFCs). Structural ordering variation is often driven by chemical composition, which directly correlates with their chemical/physical properties. In the present work, we develop a comprehensive functional perovskite-type phase diagram for the Ba-Ca-Ta-O quaternary system Ba₃Ca_1+xTa_2−xO_9−3x/2 (0 ≤ x ≤ 0.36) with a wide chemical composition between 1000 and 1550 °C, coupled with theoretical calculations to investigate the cation ordering in supercells. Furthermore, the impact of cation clustering on the diffusion pathways of O²⁻ ions was evaluated as a case study. Experimentally, precise cation ordering and other structural features are quantitively determined by TOF-neutron and synchrotron X-ray diffraction analyses. This work provides a comprehensive evaluation of some potential applications of the Ba-Ca-Ta-O quaternary system. The electrochemical impedance data were also systematically studied by impedance spectroscopy genetic programming (ISGP). The electrical conductivity was found to increase from x = 0 to x = 0.27 and then decrease for the end member when x = 0.36 due to a decrease in mobile charge carrier concentration. Interestingly, in dry air, the electrical conductivity was found to increase from x = 0 to x = 0.36. However, only Ba₃Ca_1.18Ta_1.82O_8.73 (BCT18) and Ba₃Ca_1.27Ta_1.73O_8.595 (BCT27) were found to show an increasing trend in conductivity in humid atmospheres, and this indicates that the clustering effect was pO₂ dependent.

Original language	English
Pages (from-to)	22257-22270
Number of pages	14
Journal	Journal of Materials Chemistry A
Volume	10
Issue number	41
DOIs	https://doi.org/10.1039/d2ta02725a
Publication status	Published - 26 Aug 2022

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Singh, K., Yang, H., Zhang, Z., Avdeev, M., Huq, A., Wu, D. Y., Lee, J. J., Kan, W. H., & Thangadurai, V. (2022). Evaluation of polymorphism and charge transport in a BaO-CaO-Ta₂O₅ perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy. Journal of Materials Chemistry A, 10(41), 22257-22270. https://doi.org/10.1039/d2ta02725a

@article{1107d66c5b45425faa68e9f585f28b16,

title = "Evaluation of polymorphism and charge transport in a BaO-CaO-Ta2O5 perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy",

abstract = "Among the alkaline earth-based perovskite oxides, the Ba-based perovskites have superior chemical stability and tunable electrical/catalytic property via chemical substitution/doping. One of the best-known examples is Ba3Ca1.18Nb1.82O8.73 as a ceramic proton conductor for all-solid-state steam electrolysis and solid oxide fuel cells (SOFCs). Structural ordering variation is often driven by chemical composition, which directly correlates with their chemical/physical properties. In the present work, we develop a comprehensive functional perovskite-type phase diagram for the Ba-Ca-Ta-O quaternary system Ba3Ca1+xTa2−xO9−3x/2 (0 ≤ x ≤ 0.36) with a wide chemical composition between 1000 and 1550 °C, coupled with theoretical calculations to investigate the cation ordering in supercells. Furthermore, the impact of cation clustering on the diffusion pathways of O2− ions was evaluated as a case study. Experimentally, precise cation ordering and other structural features are quantitively determined by TOF-neutron and synchrotron X-ray diffraction analyses. This work provides a comprehensive evaluation of some potential applications of the Ba-Ca-Ta-O quaternary system. The electrochemical impedance data were also systematically studied by impedance spectroscopy genetic programming (ISGP). The electrical conductivity was found to increase from x = 0 to x = 0.27 and then decrease for the end member when x = 0.36 due to a decrease in mobile charge carrier concentration. Interestingly, in dry air, the electrical conductivity was found to increase from x = 0 to x = 0.36. However, only Ba3Ca1.18Ta1.82O8.73 (BCT18) and Ba3Ca1.27Ta1.73O8.595 (BCT27) were found to show an increasing trend in conductivity in humid atmospheres, and this indicates that the clustering effect was pO2 dependent.",

author = "Kalpana Singh and Hua Yang and Zheyu Zhang and Maxim Avdeev and Ashfia Huq and Wu, {Dong Ying} and Lee, {Jey Jau} and Kan, {Wang Hay} and Venkataraman Thangadurai",

note = "W. H. K. acknowledges the very helpful discussion with Dr Kirill Okhotnikov about the Supercell program. We thank Drs Bohang Song and Melanie Kirkham at ORNL for assistance with neutron measurement. The POWGEN beamline at ORNL was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. W. H. K. appreciates the beamtime in ECHIDNA granted by the Australian Centre for Neutron Scattering (ACNS) in ANSTO. The Natural Sciences and Engineering Research Council of Canada (NSERC) has supported this work through Discovery Grants to V. T. (Award number RGPIN-2016-03853). V. T. and K. S. also acknowledge funding from the Canada First Research Excellence Fund (CFREF) at the University of Calgary. This work was also supported by the National Natural Science Foundation of China (11805034, U1930102 and 21704105) and Natural Science Foundation of Guangdong Province (2017A030313021).",

year = "2022",

month = aug,

day = "26",

doi = "10.1039/d2ta02725a",

language = "English",

volume = "10",

pages = "22257--22270",

journal = "Journal of Materials Chemistry A",

issn = "2050-7488",

publisher = "ROYAL SOC CHEMISTRY",

number = "41",

}

Singh, K, Yang, H, Zhang, Z, Avdeev, M, Huq, A, Wu, DY, Lee, JJ, Kan, WH & Thangadurai, V 2022, 'Evaluation of polymorphism and charge transport in a BaO-CaO-Ta₂O₅ perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy', Journal of Materials Chemistry A, vol. 10, no. 41, pp. 22257-22270. https://doi.org/10.1039/d2ta02725a

Evaluation of polymorphism and charge transport in a BaO-CaO-Ta₂O₅ perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy. / Singh, Kalpana; Yang, Hua; Zhang, Zheyu et al.
In: Journal of Materials Chemistry A, Vol. 10, No. 41, 26.08.2022, p. 22257-22270.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Evaluation of polymorphism and charge transport in a BaO-CaO-Ta2O5 perovskite phase diagram using TOF-neutron and synchrotron X-ray diffraction, the bond-valence method and impedance spectroscopy

AU - Singh, Kalpana

AU - Yang, Hua

AU - Zhang, Zheyu

AU - Avdeev, Maxim

AU - Huq, Ashfia

AU - Wu, Dong Ying

AU - Lee, Jey Jau

AU - Kan, Wang Hay

AU - Thangadurai, Venkataraman

N1 - W. H. K. acknowledges the very helpful discussion with Dr Kirill Okhotnikov about the Supercell program. We thank Drs Bohang Song and Melanie Kirkham at ORNL for assistance with neutron measurement. The POWGEN beamline at ORNL was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. W. H. K. appreciates the beamtime in ECHIDNA granted by the Australian Centre for Neutron Scattering (ACNS) in ANSTO. The Natural Sciences and Engineering Research Council of Canada (NSERC) has supported this work through Discovery Grants to V. T. (Award number RGPIN-2016-03853). V. T. and K. S. also acknowledge funding from the Canada First Research Excellence Fund (CFREF) at the University of Calgary. This work was also supported by the National Natural Science Foundation of China (11805034, U1930102 and 21704105) and Natural Science Foundation of Guangdong Province (2017A030313021).

PY - 2022/8/26

Y1 - 2022/8/26

N2 - Among the alkaline earth-based perovskite oxides, the Ba-based perovskites have superior chemical stability and tunable electrical/catalytic property via chemical substitution/doping. One of the best-known examples is Ba3Ca1.18Nb1.82O8.73 as a ceramic proton conductor for all-solid-state steam electrolysis and solid oxide fuel cells (SOFCs). Structural ordering variation is often driven by chemical composition, which directly correlates with their chemical/physical properties. In the present work, we develop a comprehensive functional perovskite-type phase diagram for the Ba-Ca-Ta-O quaternary system Ba3Ca1+xTa2−xO9−3x/2 (0 ≤ x ≤ 0.36) with a wide chemical composition between 1000 and 1550 °C, coupled with theoretical calculations to investigate the cation ordering in supercells. Furthermore, the impact of cation clustering on the diffusion pathways of O2− ions was evaluated as a case study. Experimentally, precise cation ordering and other structural features are quantitively determined by TOF-neutron and synchrotron X-ray diffraction analyses. This work provides a comprehensive evaluation of some potential applications of the Ba-Ca-Ta-O quaternary system. The electrochemical impedance data were also systematically studied by impedance spectroscopy genetic programming (ISGP). The electrical conductivity was found to increase from x = 0 to x = 0.27 and then decrease for the end member when x = 0.36 due to a decrease in mobile charge carrier concentration. Interestingly, in dry air, the electrical conductivity was found to increase from x = 0 to x = 0.36. However, only Ba3Ca1.18Ta1.82O8.73 (BCT18) and Ba3Ca1.27Ta1.73O8.595 (BCT27) were found to show an increasing trend in conductivity in humid atmospheres, and this indicates that the clustering effect was pO2 dependent.

AB - Among the alkaline earth-based perovskite oxides, the Ba-based perovskites have superior chemical stability and tunable electrical/catalytic property via chemical substitution/doping. One of the best-known examples is Ba3Ca1.18Nb1.82O8.73 as a ceramic proton conductor for all-solid-state steam electrolysis and solid oxide fuel cells (SOFCs). Structural ordering variation is often driven by chemical composition, which directly correlates with their chemical/physical properties. In the present work, we develop a comprehensive functional perovskite-type phase diagram for the Ba-Ca-Ta-O quaternary system Ba3Ca1+xTa2−xO9−3x/2 (0 ≤ x ≤ 0.36) with a wide chemical composition between 1000 and 1550 °C, coupled with theoretical calculations to investigate the cation ordering in supercells. Furthermore, the impact of cation clustering on the diffusion pathways of O2− ions was evaluated as a case study. Experimentally, precise cation ordering and other structural features are quantitively determined by TOF-neutron and synchrotron X-ray diffraction analyses. This work provides a comprehensive evaluation of some potential applications of the Ba-Ca-Ta-O quaternary system. The electrochemical impedance data were also systematically studied by impedance spectroscopy genetic programming (ISGP). The electrical conductivity was found to increase from x = 0 to x = 0.27 and then decrease for the end member when x = 0.36 due to a decrease in mobile charge carrier concentration. Interestingly, in dry air, the electrical conductivity was found to increase from x = 0 to x = 0.36. However, only Ba3Ca1.18Ta1.82O8.73 (BCT18) and Ba3Ca1.27Ta1.73O8.595 (BCT27) were found to show an increasing trend in conductivity in humid atmospheres, and this indicates that the clustering effect was pO2 dependent.

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JO - Journal of Materials Chemistry A

JF - Journal of Materials Chemistry A

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