Sr2(Mg1-xGax)Ge2O7+0.5x: Melilite-type oxygen ionic conductor associated with fivefold coordinated germanium and gallium

Hee Jung Park; Tae Gon Kim; Chan Kwak; Doh Won Jung; Sangmock Lee; Kyu Hyoung Lee

doi:10.1016/j.jpowsour.2014.11.088

Sr₂(Mg_1-xGa_x)Ge₂O_7+0.5x: Melilite-type oxygen ionic conductor associated with fivefold coordinated germanium and gallium

Hee Jung Park, Tae Gon Kim, Chan Kwak, Doh Won Jung, Sangmock Lee, Kyu Hyoung Lee

Department of Materials Science and Engineering

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

9 Citations (Scopus)

Abstract

We demonstrate a new type of oxygen ionic conductor, Sr₂(Mg_1-xGa_x)Ge₂O_7+0.5x with a melilite-type structure. The oxygen-ion conductivity of Sr₂Mg_0.8Ga_0.2Ge₂O_7.1 is measured as 10^-4 S/cm at 800°C using both 2-probe ac impedance and 4-probe dc measurements, and hardly depends on Po₂ indicating that the main charge carriers are interstitial oxygen ions. Based on total energy calculations, it is suggested that a Ge⁴⁺ ion as well as Ga³⁺ contributes to the ionic conduction of interstitial oxygen through the coordination changes from fourfold to fivefold.

Original language	English
Pages (from-to)	884-887
Number of pages	4
Journal	Journal of Power Sources
Volume	275
DOIs	https://doi.org/10.1016/j.jpowsour.2014.11.088
Publication status	Published - 2015 Feb 1

Bibliographical note

Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.

All Science Journal Classification (ASJC) codes

Renewable Energy, Sustainability and the Environment
Energy Engineering and Power Technology
Physical and Theoretical Chemistry
Electrical and Electronic Engineering

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This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.jpowsour.2014.11.088

Cite this

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title = "Sr2(Mg1-xGax)Ge2O7+0.5x: Melilite-type oxygen ionic conductor associated with fivefold coordinated germanium and gallium",

abstract = "We demonstrate a new type of oxygen ionic conductor, Sr2(Mg1-xGax)Ge2O7+0.5x with a melilite-type structure. The oxygen-ion conductivity of Sr2Mg0.8Ga0.2Ge2O7.1 is measured as 10-4 S/cm at 800°C using both 2-probe ac impedance and 4-probe dc measurements, and hardly depends on Po2 indicating that the main charge carriers are interstitial oxygen ions. Based on total energy calculations, it is suggested that a Ge4+ ion as well as Ga3+ contributes to the ionic conduction of interstitial oxygen through the coordination changes from fourfold to fivefold.",

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T2 - Melilite-type oxygen ionic conductor associated with fivefold coordinated germanium and gallium

AU - Park, Hee Jung

AU - Kim, Tae Gon

AU - Kwak, Chan

AU - Jung, Doh Won

AU - Lee, Sangmock

AU - Lee, Kyu Hyoung

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AB - We demonstrate a new type of oxygen ionic conductor, Sr2(Mg1-xGax)Ge2O7+0.5x with a melilite-type structure. The oxygen-ion conductivity of Sr2Mg0.8Ga0.2Ge2O7.1 is measured as 10-4 S/cm at 800°C using both 2-probe ac impedance and 4-probe dc measurements, and hardly depends on Po2 indicating that the main charge carriers are interstitial oxygen ions. Based on total energy calculations, it is suggested that a Ge4+ ion as well as Ga3+ contributes to the ionic conduction of interstitial oxygen through the coordination changes from fourfold to fivefold.

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