An efficient algorithm for finding the minimum energy path for cation migration in ionic materials.

Area of Science:

• Materials Science
• Computational Chemistry
• Solid-State Physics

Background:

• The Nudged Elastic Band (NEB) method is crucial for determining ion migration pathways and energy barriers in materials.
• Current NEB calculations, especially with density functional theory (DFT), are computationally expensive and prone to convergence issues and instabilities.
• Existing linear interpolation initialization can lead to slow convergence and divergence, particularly for curved paths or when images approach non-diffusing species.

Purpose of the Study:

• To develop a novel scheme for accelerating NEB calculations through improved path initialization and energy estimation.
• To enhance the stability and efficiency of calculating ion diffusion pathways in materials.
• To facilitate high-throughput computational screening of materials for energy storage applications.

Main Methods:

• Proposed a new initialization scheme for NEB calculations using a static potential derived from DFT charge density.
• Implemented a workflow for improved path initialization and associated energy estimation.
• Validated the method for cation migration in ionic frameworks.

Main Results:

• The new initialization method reproduced the true NEB path with <0.2 Å deviation.
• Achieved up to 25% improvement in NEB calculation runtimes.
• The approximated energy barrier showed errors within 20 meV of the NEB value, reducing computational cost by up to 5x.
• Significantly enhanced calculation stability by avoiding unphysical image initialization.

Conclusions:

• The proposed scheme offers a more stable and computationally efficient alternative for NEB calculations.
• This advancement resolves a key obstacle in computational screening of intercalation compounds for batteries.
• Enables efficient and reliable calculations of diffusion pathways for materials discovery.