Skip to content

Research at St Andrews

Dependence of activation energy on temperature and structure in lanthanum gallates

Research output: Other contribution

Standard

Dependence of activation energy on temperature and structure in lanthanum gallates. / Bradley, J; Slater, PR; Ishihara, T; Irvine, John Thomas Sirr.

2003.

Research output: Other contribution

Harvard

Bradley, J, Slater, PR, Ishihara, T & Irvine, JTS 2003, Dependence of activation energy on temperature and structure in lanthanum gallates..

APA

Bradley, J., Slater, PR., Ishihara, T., & Irvine, J. T. S. (2003). Dependence of activation energy on temperature and structure in lanthanum gallates.

Vancouver

Bradley J, Slater PR, Ishihara T, Irvine JTS. Dependence of activation energy on temperature and structure in lanthanum gallates. 2003.

Author

Bradley, J ; Slater, PR ; Ishihara, T ; Irvine, John Thomas Sirr. / Dependence of activation energy on temperature and structure in lanthanum gallates. 2003.

Bibtex - Download

@misc{be98d7524e9b4adabf6ad6b2c1cb8400,
title = "Dependence of activation energy on temperature and structure in lanthanum gallates",
abstract = "The parent phase of the lanthanum gallate series of electrolytes, LaGaO3, is orthorhombic at room temperature and rhombohedral between 250 and 1000degreesC (1-3). Our high resolution neutron powder studies on the doped phases, La0.9Sr0.1Ga0.8Mg0.2O3 and its Ba-analogue, show significant structural differences from the parent phase that have direct bearing on the ionic conduction process that can easily be understood in terms of the degree of tilting of the GaO6 octahedra. The monoclinic form at room temperature has a higher degree of distortion associated with the octahedra and undergoes phase transitions at elevated temperatures that relate to the change in activation energy for the ionic conduction obtained from AC impedance spectroscopy data. In particular the gradual alignment of the octahedra above 300 (Ba) or 500degreesC (Sr) as the cell heads toward cubic symmetry produces a slow, temperature-dependent decrease in Ea for ionic conduction as the tilting of the GaO6 is reduced, thereby facilitating the migration of the oxide ion. AC impedance studies of the doped lanthanum gallates reveal a similar activation energy dependence for the barium and strontium analogues with an activation energy of I eV below the transition to rhombohedral with a gradual decrease towards 0.6 eV at the highest temperature.",
keywords = "OXYGEN-ION CONDUCTIVITY, PEROVSKITE-TYPE OXIDE, DOPED LAGAO3, LA0.9SR0.1GA0.8MG0.2O2.85, ELECTROLYTE, MAGNESIUM, STRONTIUM, STABILITY",
author = "J Bradley and PR Slater and T Ishihara and Irvine, {John Thomas Sirr}",
note = "Electrochemical Society Proceedings",
year = "2003",
language = "English",
volume = "2003-07",
type = "Other",

}

RIS (suitable for import to EndNote) - Download

TY - GEN

T1 - Dependence of activation energy on temperature and structure in lanthanum gallates

AU - Bradley, J

AU - Slater, PR

AU - Ishihara, T

AU - Irvine, John Thomas Sirr

N1 - Electrochemical Society Proceedings

PY - 2003

Y1 - 2003

N2 - The parent phase of the lanthanum gallate series of electrolytes, LaGaO3, is orthorhombic at room temperature and rhombohedral between 250 and 1000degreesC (1-3). Our high resolution neutron powder studies on the doped phases, La0.9Sr0.1Ga0.8Mg0.2O3 and its Ba-analogue, show significant structural differences from the parent phase that have direct bearing on the ionic conduction process that can easily be understood in terms of the degree of tilting of the GaO6 octahedra. The monoclinic form at room temperature has a higher degree of distortion associated with the octahedra and undergoes phase transitions at elevated temperatures that relate to the change in activation energy for the ionic conduction obtained from AC impedance spectroscopy data. In particular the gradual alignment of the octahedra above 300 (Ba) or 500degreesC (Sr) as the cell heads toward cubic symmetry produces a slow, temperature-dependent decrease in Ea for ionic conduction as the tilting of the GaO6 is reduced, thereby facilitating the migration of the oxide ion. AC impedance studies of the doped lanthanum gallates reveal a similar activation energy dependence for the barium and strontium analogues with an activation energy of I eV below the transition to rhombohedral with a gradual decrease towards 0.6 eV at the highest temperature.

AB - The parent phase of the lanthanum gallate series of electrolytes, LaGaO3, is orthorhombic at room temperature and rhombohedral between 250 and 1000degreesC (1-3). Our high resolution neutron powder studies on the doped phases, La0.9Sr0.1Ga0.8Mg0.2O3 and its Ba-analogue, show significant structural differences from the parent phase that have direct bearing on the ionic conduction process that can easily be understood in terms of the degree of tilting of the GaO6 octahedra. The monoclinic form at room temperature has a higher degree of distortion associated with the octahedra and undergoes phase transitions at elevated temperatures that relate to the change in activation energy for the ionic conduction obtained from AC impedance spectroscopy data. In particular the gradual alignment of the octahedra above 300 (Ba) or 500degreesC (Sr) as the cell heads toward cubic symmetry produces a slow, temperature-dependent decrease in Ea for ionic conduction as the tilting of the GaO6 is reduced, thereby facilitating the migration of the oxide ion. AC impedance studies of the doped lanthanum gallates reveal a similar activation energy dependence for the barium and strontium analogues with an activation energy of I eV below the transition to rhombohedral with a gradual decrease towards 0.6 eV at the highest temperature.

KW - OXYGEN-ION CONDUCTIVITY

KW - PEROVSKITE-TYPE OXIDE

KW - DOPED LAGAO3

KW - LA0.9SR0.1GA0.8MG0.2O2.85

KW - ELECTROLYTE

KW - MAGNESIUM

KW - STRONTIUM

KW - STABILITY

M3 - Other contribution

VL - 2003-07

ER -

Related by author

  1. Non-stoichiometry, structure and properties of proton-conducting perovskite oxides

    Li, S. & Irvine, J. T. S., Mar 2021, In: Solid State Ionics. 361, 115571.

    Research output: Contribution to journalReview articlepeer-review

  2. Upscaling of co-impregnated La0.20Sr0.25Ca0.45TiO3 anodes for solid oxide fuel cells: a progress report on a decade of academic-industrial collaboration

    Price, R., Cassidy, M., Grolig, J. G., Longo, G. G., Weissen, U. G., Mai, A. G. & Irvine, J. T. S., 12 Feb 2021, In: Advanced Energy Materials. Early View, 21 p., 2003951.

    Research output: Contribution to journalReview articlepeer-review

  3. Microwave irradiation synthesis to obtain La0.7-xPrxCa0.3MnO3 perovskites: electrical and electrochemical performance

    Ferrel-Alvarez, A. C., Domínguez-Crespo, M. A., Cong, H., Torres-Huerta, A. M., Palma-Ramírez, D. & Irvine, J. T. S., 15 Jan 2021, In: Journal of Alloys and Compounds. 851, 156882.

    Research output: Contribution to journalArticlepeer-review

  4. Graphitic-C3N4 coated floating glass beads for photocatalytic destruction of synthetic and natural organic compounds in water under UV light

    Hui, J., Pestana, C. J., Caux, M., Gunaratne, H. Q. N., Edwards, C., Robertson, P. K. J., Lawton, L. A. & Irvine, J. T. S., 15 Jan 2021, In: Journal of Photochemistry and Photobiology A: Chemistry. 405, 112935.

    Research output: Contribution to journalArticlepeer-review

  5. Activation of anion redox in P3 structure cobalt-doped sodium manganese oxide via introduction of transition metal vacancies

    Kim, E. J., Mofredj, K., Pickup, D., Chadwick, A., Irvine, J. T. S. & Armstrong, R., 1 Jan 2021, In: Journal of Power Sources. 481, 229010.

    Research output: Contribution to journalArticlepeer-review

ID: 279355

Top