Entropic stabilization enhanced ionic transport in (La, Nd, Sm, Gd)AlO₃ perovskite electrolytes

Area of Science:

• Materials Science
• Solid-State Chemistry
• Electrochemistry

Background:

• Entropy-stabilized oxides (ESOs) are emerging materials for enhanced ionic transport.
• Perovskite electrolytes traditionally rely on doping to improve conductivity.
• Compositional disorder in ESOs offers a new design paradigm.

Purpose of the Study:

• To synthesize and characterize a novel entropy-stabilized oxide (ESO) perovskite.
• To investigate the ionic conductivity and transport mechanisms of the new ESO.
• To explore the potential of ESOs for electrochemical energy devices.

Main Methods:

• Synthesis of (La₀.₂₅Nd₀.₂₅Sm₀.₂₅Gd₀.₂₅)AlO₃ via entropy stabilization.
• Ionic conductivity measurements at elevated temperatures (up to 500°C).
• Combined computational and experimental analyses (e.g., band structure, surface effects).

Main Results:

• Achieved ionic conductivity exceeding 0.23 S/cm at 500°C for the novel ESO.
• Demonstrated significantly higher conductivity compared to pristine LaAlO₃.
• Identified entropy-induced band narrowing, surface band bending, and local electric fields as key factors.

Conclusions:

• Entropy stabilization provides a novel pathway for designing high-performance perovskite electrolytes.
• A new ion transport mechanism, distinct from doping-induced defects, was revealed.
• Findings advance material design for intermediate-temperature solid oxide fuel cells (SOFCs) and proton-conducting fuel cells (PCFCs).