Force Fields for High Concentration Aqueous KOH Solutions and Zincate Ions

Area of Science:

• Electrochemistry
• Computational Chemistry
• Materials Science

Background:

• Increasing interest in electrochemical devices utilizing highly alkaline electrolytes.
• Need for accurate computational models to simulate these systems.
• Importance of understanding ion interactions in concentrated solutions.

Purpose of the Study:

• To investigate and compare two force fields for simulating potassium hydroxide (KOH) at high concentrations.
• To develop and validate force field parameters for zincate ions in these solutions.
• To assess the predictive accuracy of the force fields against experimental data.

Main Methods:

• Molecular dynamics simulations using two distinct force fields: FNB (SPC/E water) and FHM (TIP4P/2005 water).
• Development of specific parameters for zincate ions.
• Comparison of simulated properties (density, viscosity) with experimental data for KOH and zincate solutions.

Main Results:

• The FHM model demonstrated superior agreement with experimental density and viscosity for KOH compared to the FNB model.
• Both force fields provided reasonable predictions for zincate solution properties.
• The FHM parameters offered a more accurate prediction of solution viscosity.

Conclusions:

• The FHM force field, utilizing TIP4P/2005 water, is recommended for simulating concentrated KOH solutions.
• The developed zincate ion parameters enable more accurate simulations of zincate/KOH systems.
• These validated force field parameters will be valuable for future computational studies of electrochemical devices.