Silicon Electrodeposition From the KCl-K 2 SiF 6 Melt

In this work, possible use of the KCl-K2SiF6 system for silicon electrodeposition has been studied. Kinetics of silicon electroreduction on glassy carbon in the KCl melt with the addition of 1 and 5 wt% K2SiF6 at 790°C was studied by electroanalytical methods (cyclic chronovoltammetry, square-wave voltammetry, chronoamperometry). Voltammetry was also used to determine equilibrium concentration of silicon containing-ions in the melt, and to estimate its decomposition rate to SiF4. It was shown that appearance of fluoride ions provides the required amount of silicon ions for the electrolytic refining of silicon due to the decomposition of K2SiF6.