Modifying grain boundary ionic/electronic transport in nano-Sr- And Mg- Doped LaGAO3-δ by sintering variations

Ting Chen, George F. Harrington, Junko Matsuda, Kazunari Sasaki, David Pham, Erica L. Corral, Nicola H. Perry

研究成果: ジャーナルへの寄稿記事

抜粋

Perovskite La0.9Sr0.1Ga0.9Mg0.1O3-δ (LSGM) is one of the fastest known oxide ion conductors, with reported enhanced p-type electronic transference numbers at grain boundaries, attributed to space charge effects. As this material is applied as a solid oxide fuel/electrolysis cell electrolyte, it is of interest to learn how its mixed conductivity may be tailored. Field assisted sintering technique/spark plasma sintering (FAST/SPS) and conventional sintering without field or pressure were employed to prepare pellets with various grain sizes, in order to systematically assess the influence of processing route on the mixed conductivity. AC-impedance spectroscopy and the brick layer model were applied to determine local conductivities as a function of temperature, oxygen partial pressure, and dc bias. With increasing sintering temperature and grain size, the following trends were observed: larger electrical grain boundary (GB) widths, higher GB potentials, lower specific GB conductivity, greater dc-bias dependence of GB conductivity, higher pO2-dependence of GB conductivity indicating higher electronic transference numbers, and lower pre-exponential factor for specific GB conductivity. These results suggest an increasing GB space charge effect with increasing sintering temperature/grain size, which coincided with increasing compositional uniformity by TEM and EDS. The results confirm that sintering route is an important variable for tailoring mixed conduction.

元の言語英語
ページ(範囲)F569-F580
ジャーナルJournal of the Electrochemical Society
166
発行部数10
DOI
出版物ステータス出版済み - 1 1 2019

    フィンガープリント

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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