Single sublattice endotaxial phase separation driven by charge frustration in a complex oxide

Area of Science:

• Materials Science
• Solid-State Chemistry
• Energy Storage and Conversion

Background:

• Complex transition-metal oxides, particularly cubic ABO3 perovskites, are vital functional materials for energy and information storage.
• Perovskite structure involves larger A cations defining an AO3 network with smaller B cations occupying octahedral sites.

Purpose of the Study:

• To investigate the structural and compositional modifications induced by introducing chemically mismatched octahedral cations into cubic perovskite oxides.
• To explore the potential of creating endotaxial nanocomposites with enhanced properties and stability.

Main Methods:

• Synthesis of cubic perovskite oxide parent phases.
• Introduction of chemically mismatched octahedral cations to modify the B sublattice.
• Structural and compositional analysis to characterize the resulting nanocomposite phases.

Main Results:

• Modification of structure and composition beyond the unit cell length scale on the B sublattice.
• Formation of an endotaxial nanocomposite comprising two distinct cubic perovskite phases (B-site cation-ordered and -disordered).
• Enhanced stability against hexagonal phase formation compared to the single-phase parent.
• Superior solid oxide fuel cell cathode performance due to synergistic integration of composite phases.

Conclusions:

• Introducing chemically mismatched cations into cubic perovskites creates stable endotaxial nanocomposites with unique properties.
• The nanocomposite structure, with coherent interfaces, significantly enhances solid oxide fuel cell cathode performance.
• This approach offers a promising strategy for designing advanced functional materials for energy applications.