Calculations of silicon complexes in KF–KCl–KI–K2SiF6 and KF–KCl–KI–K2SiF6–SiO2 molten electrolytes

The stability of silicon complexes formed in KF-KI-KCl-K2SiF6 and KF-KCl-KI-K2SiF6-SiO2 was studied using the density functional theory method. The calculations of the bond energy Si-F and Si-I were performed. Conclusions about the stability of silicon complexes containing different amounts of iodine ions in the inner coordination sphere were made. All oxyfluoride silicate complex compounds became extremely unstable when replacing fluoride with iodide ion.