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 journalArticlepeer-review

13 Citations (SciVal)


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
Pages (from-to)F569-F580
Number of pages13
JournalJournal of the Electrochemical Society
Issue number10
Publication statusPublished - 30 May 2019

Bibliographical note

Funding Information:
This research has been primarily supported by the U.S. NSF and by JSPS through a Partnerships in International Research and Education (PIRE) Program (NSF grant # 1545907). TC acknowledges a JSPS Doctoral Fellowship (# 201702103). GFH acknowledges a JSPS Kak-enhi Grant-in-aid for Young Scientist (B) Award (No. JP16K18235), Progress-100 funding for Kyushu University-MIT-collaboration, and KS and GFH acknowledge the Center-of-Innovation program. NHP, TC, GFH, and KS would also like to acknowledge the support of the International Institute for Carbon Neutral Energy Research (WPI-I2CNER) sponsored by the Japanese Ministry of Education, Culture, Sports, Science and Technology.

Publisher Copyright:
© The Author(s) 2019.

ASJC Scopus subject areas

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


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