Electrodeposition of Silicon from the Low-Melting LiCl-KCl-CsCl-K2SiF6 Electrolytes

The possibility of silicon electrodeposition from the low-melting LiCl-KCl-CsCl-K 2 SiF 6 electrolytes has been studied. The stability of a silicon-containing additive was studied by cyclic voltammetry, and the rate constant of the chemical reaction of SiF 4 release at a temperature of 827 K was calculated. It is determined that the constants of velocity values in the melt based on eutectic composition are 2 orders of magnitude higher, which indicates a higher rate of formation of volatile compounds. Cyclic voltammetry was also used to study the electrochemical behavior of K 2 SiF 6 in the melts under study. It was found that the silicon electroreduction at the cathode is not reversible and proceeds in one 4-electron reaction. The diffusion coefficient calculated by the Matsuda-Ayabe equation was 0.72·10 −5 cm 2 ·s −1 at temperature of 823 K. According to the obtained voltammograms, the parameters for the silicon electrodeposition were selected. At a potential of −0.4 V vs QRE, dendritic silicon deposits were obtained.