Crystal morphology of LiOH·H2O in different solvents by molecular dynamics simulation

Abstract

In this study, the crystal morphology of LiOH·H2O in different solvents was predicated through molecular dynamics (MD) simulation. Modified attachment energy (MAE) model was to predict the crystal morphology by calculating the relative growth rate of LiOH·H2O in H2O, CH3CH2OH, and CH3CH2OH/H2O mixed solvent system. The molecular force between the crystal face and the solvent was also analyzed. The calculated results indicate that the main growth surfaces of LiOH·H2O are (1 1 0), (0 0 1), (1 1 − 1), and (2 0 − 1) faces. The crystal habit of LiOH·H2O in the solvent H2O is bulky with a regular shape and a small aspect ratio. The crystal habit of LiOH·H2O in the solvent CH3CH2OH is rhombus, with the most important growth surface of (1 1 0) and an aspect ratio of 1.978. The mixed solvents of CH3CH2OH/H2O with different mass ratios (1:1, 1:3, 3:1) affect the morphology of LiOH·H2O. With the increase of CH3CH2OH content, the exposed area of (2 0 − 1) face tends to be smaller gradually, while the surface of (1 1 0) face was constantly apparent. The mass ratio of 3:1 results in the disappearance of the (2 0 − 1) face. Calculation results using the radial distribution function (RDF) between the crystal face and the solvent CH3CH2OH or H2O show that the long-range electrostatic force is dominant in the interaction between atoms, and a weak Van Der Waals force emerges.