Long-range oxygen ordering linked to topotactic oxygen release in Pr2NiO4+δ fuel cell cathode material

R. Dutta, A. Maity, A. Marsicano, M. Ceretti, D. Chernyshov, A. Bosak, A. Villesuzanne, G. Roth, G. Perversi, W. Paulus*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

7 Citations (Web of Science)

Abstract

Solid oxide ion conductors are technologically important for oxygen membranes, sensors and solid oxide fuel cells (SOFC). However, oxygen diffusion is a thermally activated process, and materials operating at ambient temperature are rare, as the related diffusion mechanisms are poorly understood. Herein, we report a hidden spontaneous oxygen release reaction that interconverts two stoichiometric phases of the SOFC material Pr(2)NiO(4+delta)with unprecedented structural complexity at ambient temperature. A slight change in the oxygen stoichiometry from delta= 0.25 to delta= 0.225 involves a transition between two competing modulated superstructures, showing long-range translational periodicities up to 94 angstrom. Our findings demonstrate correlated oxygen diffusion within the bulk phase at room temperature, which is accompanied by the formation of long-range modulated superstructures up to the lower mesoscale. Large-scale ordered structures found here for Pr(2)NiO(4+delta)are rather indicative of non-local interactions, and are interpreted to be mediatedviastructural deformations. This unexpected behavior is discussed in terms of an unconventional understanding of low-Toxygen diffusion mechanisms and its potential to conceive and optimize oxygen ion conductors, which are an important class of compounds relevant to technological applications.
Original languageEnglish
Pages (from-to)13987-13995
Number of pages9
JournalJournal of Materials Chemistry. A, Materials for Energy and Sustainability
Volume8
Issue number28
DOIs
Publication statusPublished - 28 Jul 2020
Externally publishedYes

Keywords

  • crystal-structure
  • defect perovskite
  • diffusion
  • electrochemical-behavior
  • intercalation
  • lattice-dynamics
  • nd2nio4+delta
  • redox reactions
  • room-temperature
  • x-ray
  • ROOM-TEMPERATURE
  • LATTICE-DYNAMICS
  • ND2NIO4+DELTA
  • DEFECT PEROVSKITE
  • CRYSTAL-STRUCTURE
  • REDOX REACTIONS
  • INTERCALATION
  • ELECTROCHEMICAL-BEHAVIOR
  • X-RAY
  • DIFFUSION

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