Phase-Field Based Multiscale Modeling of Heterogeneous Solid Electrolytes: Applications to Nanoporous Li₃PS₄

Area of Science:

• Materials Science
• Electrochemistry
• Computational Modeling

Background:

• Modeling heterogeneous solid electrolytes often uses simplified microstructures.
• The critical role of filler/matrix interface features in ion conductivity has been overlooked.
• Accurate microstructure generation is essential for predicting material properties.

Purpose of the Study:

• To develop a phase-field model for generating realistic nanoporous microstructures.
• To incorporate DFT-predicted interface properties into microstructure generation.
• To accurately predict effective ion conductivity in heterogeneous solid electrolytes.

Main Methods:

• Developed a phase-field model for microstructure generation.
• Utilized density functional theory (DFT) for surface energy and depth predictions.
• Performed numerical calculations of effective ion conductivity.
• Applied effective medium theories for analytical predictions.

Main Results:

• Generated nanoporous β-Li3PS4 microstructures with varying porosity and connectivity.
• Achieved good agreement between numerical, analytical, and experimental ion conductivity values.
• Demonstrated significantly enhanced Li-ion conductivity near the percolation threshold (1.74 × 10-4 S/cm).

Conclusions:

• The phase-field model effectively generates microstructures considering interface properties.
• The multiscale approach accurately predicts effective ion conductivity in heterogeneous solid electrolytes.
• This model is broadly applicable to various solid electrolyte systems.