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.

Computer Test of a Modified Silicene/Graphite Anode for Lithium-Ion Batteries

Despite the considerable efforts made to use silicon anodes and composites based on them in lithium-ion batteries, it is still not possible to overcome the difficulties associated with low conductivity, a decrease in the bulk energy density, and side reactions. In the present work, a new design of an electrochemical cell, whose anode is made in the form of silicene on a graphite substrate, is presented. The whole system was subjected to transmutation neutron doping. The molecular dynamics method was used to study the intercalation and deintercalation of lithium in a phosphorus-doped silicene channel. The maximum uniform filling of the channel with lithium is achieved at 3% and 6% P-doping of silicene. The high mobility of Li atoms in the channel creates the prerequisites for the fast charging of the battery. The method of statistical geometry revealed the irregular nature of the packing of lithium atoms in the channel. Stresses in the channel walls arising during its maximum filling with lithium are significantly inferior to the tensile strength even in the presence of polyvacancies in doped silicene. The proposed design of the electrochemical cell is safe to operate.