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

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)F569-F580
JournalJournal of the Electrochemical Society
Volume166
Issue number10
DOIs
StatePublished - Jan 1 2019

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Grain boundaries
Sintering
Spark plasma sintering
Electric space charge
Oxides
Brick
Electrolysis
Partial pressure
Perovskite
Temperature
Electrolytes
Energy dispersive spectroscopy
Spectroscopy
Ions
Oxygen
Transmission electron microscopy
Processing

ASJC Scopus subject areas

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

Cite this

Modifying grain boundary ionic/electronic transport in nano-Sr- And Mg- Doped LaGAO3-δ by sintering variations. / Chen, Ting; Harrington, George F.; Matsuda, Junko; Sasaki, Kazunari; Pham, David; Corral, Erica L.; Perry, Nicola H.

In: Journal of the Electrochemical Society, Vol. 166, No. 10, 01.01.2019, p. F569-F580.

Research output: Contribution to journalArticle

Chen, Ting ; Harrington, George F. ; Matsuda, Junko ; Sasaki, Kazunari ; Pham, David ; Corral, Erica L. ; Perry, Nicola H. / Modifying grain boundary ionic/electronic transport in nano-Sr- And Mg- Doped LaGAO3-δ by sintering variations. In: Journal of the Electrochemical Society. 2019 ; Vol. 166, No. 10. pp. F569-F580.
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