Direct Measurement of Oxygen Mass Transport at the Nanoscale

Federico Baiutti, Francesco Chiabrera, David Diercks, Andrea Cavallaro, Lluis Yedra, Lluis Lopez-Conesa, Sonia Estrade, Francesca Peiro, Alex Morata, Ainara Aguadero, Albert Tarancon*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Tuning oxygen mass transport properties at the nanoscale offers a promising approach for developing high performing energy materials. A number of strategies for engineering interfaces with enhanced oxygen diffusivity and surface exchange have been proposed. However, the origin and the magnitude of such local effects remain largely undisclosed to date due to the lack of direct measurement tools with sufficient resolution. In this work, atom probe tomography with sub-nanometer resolution is used to study oxygen mass transport on oxygen-isotope exchanged thin films of lanthanum chromite. A direct 3D visualization of nanoscaled highly conducting oxygen incorporation pathways along grain boundaries, with reliable quantification of the oxygen kinetic parameters and correlative link to local chemistries, is presented. Combined with finite element simulations of the exact nanostructure, isotope exchange-atom probe tomography allowed quantifying an enhancement in the grain boundary oxygen diffusivity and in the surface exchange coefficient of lanthanum chromite of about 4 and 3 orders of magnitude, respectively, compared to the bulk. This remarkable increase of the oxygen kinetics in an interface-dominated material is unambiguously attributed to grain boundary conduction highways thanks to the use of a powerful technique that can be straightforwardly extended to the study of currently inaccessible multiple nanoscale mass transport phenomena.
Original languageEnglish
Article numbere2105622
JournalAdvanced Materials
Volume33
Issue number48
Number of pages8
ISSN0935-9648
DOIs
Publication statusPublished - 2021

Keywords

  • Electrode materials
  • Fuel cells
  • Grain boundaries
  • Mixed ionic-electronic conductors
  • Oxygen kinetics
  • Thin films

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