Study of the structure of a multicomponent salt melt using molecular dynamics modeling

The composition of the electrolyte is critical in the electrodeposition of high-purity silicon. In this work, molecular dynamics modeling of the preparation of liquid salt melt KF-KCl-KI and a detailed study of its structure based on the method of statistical geometry have been performed. Partial radial distribution functions reflect the size of the ions under consideration and the averaged structure of the generated ionic subsystems. Halogen subsystems have domed angular distributions of nearest geometric neighbors, a wide range of face types of combined polyhedra, and fifth order rotational symmetry. The shape of the distribution of distances to the nearest neighbors of a given type depends on the amount of these ions in the melt. Small-scale thermal fluctuations in the halogen subsystems are predominantly represented by small triangular faces in combined polyhedra. The electrodeposition of silicon was carried out in a homogeneous salt melt, in which each halogen ion had from one to three close contacts with halogen ions of any other type. The simulations performed provide a fundamental understanding of the structure of the electrolyte molten salts used to produce solar silicon.