Local Distortions and Dynamics in Hydrated Y-Doped BaZrO₃

Area of Science:

• Materials Science
• Solid-State Chemistry
• Computational Materials Science

Background:

• Yttrium-doped Barium Zirconate (BaZrO3) is a key material for intermediate temperature solid oxide fuel cells.
• Proton conduction is crucial for efficient fuel cell operation.

Purpose of the Study:

• To investigate proton conduction mechanisms in Y-doped BaZrO3 using computational methods.
• To understand the relationship between lattice structure and proton mobility.

Main Methods:

• Density Functional Theory (DFT) static calculations were performed.
• DFT-based Molecular Dynamics (DFT-MD) simulations were employed.
• Geometry optimizations identified key structural configurations.

Main Results:

• A correlation was found between metal-oxygen-metal angle bending and cell energies.
• Inward bending and proximity to dopants resulted in lower energies and stronger hydrogen bonds.
• DFT-MD simulations revealed dynamic lattice distortions and proton jump mechanisms.

Conclusions:

• Proton diffusion is influenced by inward and outward bending configurations.
• Intra-octahedral jumps are favored from outward configurations, while inward configurations facilitate oxygen rotations.
• Calculated diffusion coefficients and activation energies align with experimental data.