Simulations of LiCl-Water: The Effects of Concentration and Supercooling

Abstract: Aqueous solutions of LiCl are probably the most studied electrolyte solutions related to the complexity of liquid water at low temperatures. Despite the large amount of available experimental data hardly any computational studies were performed on LiCl solutions in this context. In this study, we present molecular dynamics simulations of LiCl-water at ambient and supercooled conditions spanning a large concentration range. The molecular insight gained provides information on how the presence of the ions impacts the hydrogen bond network. It is found that this influence changes appreciably when supercooled states are considered. While the local structure of water molecules beyond the first hydration shells barely changes with concentration at room temperature, a change is found for those molecules at low temperature. Additionally, we scrutinize the possibility of a phase separation in this system as indicated by several experimental studies. Our analyses do not show signs of such a phase separation at 240 K, but are consistent with a possible separation at even lower temperatures.