Hydroxide Mobility in Aqueous Systems: Combining Ab Initio Accuracy with Millisecond Timescales

Area of Science:

• Computational chemistry
• Materials science
• Physical chemistry

Background:

• Accurate simulation of ion transport is crucial for developing advanced energy materials.
• Existing methods often struggle to bridge the gap between atomic-level dynamics and macroscopic transport phenomena.

Purpose of the Study:

• To develop a multiscale simulation approach for hydroxide transport in aqueous potassium hydroxide solutions.
• To achieve near ab initio accuracy across extended timescales relevant to material applications.

Main Methods:

• Combines ab initio molecular dynamics (AIMD) with force field ensemble averaging and lattice Monte Carlo techniques.
• Captures femtosecond dielectric relaxation dynamics and extends simulations to millisecond diffusion timescales.

Main Results:

• Demonstrates accurate prediction of hydroxide conductivity over a range of concentrations using a single AIMD trajectory.
• Successfully bridges femtosecond dynamics to millisecond diffusion timescales.

Conclusions:

• The multiscale approach offers a computationally efficient and accurate method for studying hydroxide mobility.
• This technique is highly relevant for designing functional materials like anion-exchange membranes for energy applications.