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.

Keywords:

• Crystal face
• crystal morphology
• LiOH·H₂O
• modified attachment energy
• molecular dynamics simulation

Acknowledgments

The authors would like to acknowledge the assistance from Haihui Zhang, Hao Xiao, Huajing Chen, and Bingxuan He from Jiangxi University of Science and Technology.

Additional information

Funding

Project supported by the National Natural Science Foundation of China (51564019, 51674125) and the Science and Technology Project of Jiangxi Province Education Department (GJJ181501).