Non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites

S. M. Haile, G. Staneff, K. H. Ryu

Research output: Contribution to journalArticlepeer-review

262 Scopus citations

Abstract

The interrelationship between defect chemistry, non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites (doped alkaline earth cerates and zirconates) has been investigated. Non-stoichiometry, defined as the deviation of the A: M molar ratio in AMO3 from 1: 1, dramatically impacts conductivity, sinterability and chemical stability with respect to reaction with CO2. In particular, alkaline earth deficiency encourages dopant incorporation onto the A-atom site, rather than the intended M-atom site, reducing the concentration of oxygen vacancies. Transport along grain boundaries is, in general, less favorable than transport through the bulk, and thus only in fine-grained materials does microstructure impact the overall electrical properties. The chemical stability of high conductivity cerates is enhanced by the introduction of Zr. The conductivity of BaCe0.9-xZrxM0.1O3 perovskites monotonically decreases with increasing x (increasing Zr content), with the impact of Zr substitution increasing in the order M = Yb → Gd → Nd. Furthermore, the magnitude of the conductivity follows the same sequence for a given zirconium content. This result is interpreted in terms of dopant ion incorporation onto the divalent ion site.

Original languageEnglish (US)
Article number334511
Pages (from-to)1149-1160
Number of pages12
JournalJournal of Materials Science
Volume36
Issue number5
DOIs
StatePublished - Jan 1 2001

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'Non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites'. Together they form a unique fingerprint.

Cite this