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

Research output: Contribution to journalArticle

7 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)884-887
Number of pages4
JournalJournal of Power Sources
Volume275
DOIs
Publication statusPublished - 2015 Feb 1

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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