Quasi‐In Situ 4D‐STEM Mapping of Exsolution Driven Parent Matrix Restructuring in Sr 2 FeMoO 6‐δ

Small Methods, vol. 10, pp. e70809

Abstract

ABSTRACT The in situ exsolution of catalytic particles upon reduction makes double‐perovskites promising candidates for next‐generation solid oxide cells (SOCs). While recent in situ S/TEM studies have –visualized this process, these investigations have primarily focused on isolated particles rather than realistic electrode architectures and the effect of exsolution on the surrounding host matrix remains largely unexplored. Herein, a quasi‐in situ S/TEM approach is presented to investigate the impact of exsolution on a realistic Sr 2 FeMoO 6‐δ (SFM) electrode by decoupling the influence of electron‐beam‐induced artifacts. By extracting a lamella from a bulk SOC using a plasma‐FIB and performing identical‐location characterization utilizing EDS and 4D‐STEM before and after reduction captures both the chemical segregation and intrinsic structural transformations within the electrode grains. Utilizing iDPC and radial Fourier analysis (RFA), this approach reveals that surface exsolution is coupled with substantial crystallographic reorganization within the SFM matrix, evidenced by distinct domain shrinkage and localized phase gradients along grain facets. The interconnected bulk electrode geometry promotes higher exsolution density compared to isolated powder particles, underscoring the necessity of studying realistic architectures. By linking surface exsolution to matrix modification in a realistic bulk electrode geometry, this quasi‐in situ methodology provides a vital insights into the exsolution process.

Authors 8

1. Pritam Kishore Chakraborty Aachen Institute of Physical Chemistry

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Institute of Energy Technology‐ Fundamental Electrochemistry (IET‐1) Forschungszentrum Jülich GmbH Jülich Germany

   Institute of Physical Chemistry RWTH Aachen University Aachen Germany

2. Junbeom Park

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy Technology‐ Fundamental Electrochemistry (IET‐1) Forschungszentrum Jülich GmbH Jülich Germany

3. Stephanie E. Wolf

   Forschungszentrum Jülich · Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

   Affiliation as printed

   DLR Institut für Technische Thermodynamik Stuttgart Baden‐Württemberg Germany

   Institute of Energy Technology‐ Fundamental Electrochemistry (IET‐1) Forschungszentrum Jülich GmbH Jülich Germany

4. Vaibhav Vibhu

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy Technology‐ Fundamental Electrochemistry (IET‐1) Forschungszentrum Jülich GmbH Jülich Germany

5. Hongyu Sun

   Denssolutions (Netherlands)

   Affiliation as printed

   DENSsolutions B.V., Informaticalaan Delft Netherlands

6. H. Hugo Pérez Garza

   Denssolutions (Netherlands)

   Affiliation as printed

   DENSsolutions B.V., Informaticalaan Delft Netherlands

7. Shibabrata Basak corresponding

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy Technology‐ Fundamental Electrochemistry (IET‐1) Forschungszentrum Jülich GmbH Jülich Germany

8. Rüdiger‐A. Eichel Aachen Faculty of Mechanical Engineering Institute of Physical Chemistry

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Faculty of Mechanical Engineering RWTH Aachen University Aachen Germany

   Institute of Energy Technology‐ Fundamental Electrochemistry (IET‐1) Forschungszentrum Jülich GmbH Jülich Germany

   Institute of Physical Chemistry RWTH Aachen University Aachen Germany