Cation environment of BaCeO(3)-based protonic conductors: a computational study

Area of Science:

• Computational materials science
• Solid-state chemistry
• Protonic conductors

Background:

• Barium cerate (BaCeO3) is a promising material for high-temperature protonic conductors.
• Doping strategies are employed to enhance the ionic conductivity of BaCeO3.
• Understanding the relationship between dopant properties and conductivity is crucial for material design.

Purpose of the Study:

• To investigate the structural and electronic properties of pure and doped BaCeO3 using computational methods.
• To elucidate the mechanisms by which Yttrium (Y) and Indium (In) doping affect the proton conductivity.
• To develop a computational framework for studying doped BaCeO3 protonic conductors.

Main Methods:

• Geometry calculations using Hartree-Fock (HF) and Density Functional Theory (DFT) on BaCeO3 fragments.
• Investigation of monoclinic and orthorhombic crystal structures.
• Electronic structure analysis, including Partial Density of States and C-Squared Population Analysis.

Main Results:

• HF calculations accurately capture structural parameters (distances, angles) with low-level basis sets.
• Electronic structure analysis indicates that dopants should decrease local oxygen basicity to enhance conductivity.
• Local structural changes unrelated to basicity have minimal impact on conductivity.

Conclusions:

• The primary mechanism for enhanced proton conductivity in Y:BaCeO3 and In:BaCeO3 involves a reduction in local oxygen basicity.
• Computational approaches provide valuable insights for interpreting experimental findings in doped BaCeO3 systems.
• This study offers a pathway for designing improved proton conductor materials through targeted doping strategies.