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The possibility of silicon electrodeposition from the low-melting LiCl-KCl-CsCl-K2SiF6 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 SiF4 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 K2SiF6 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 coefficients calculated by the Matsuda-Ayabe equation were 3.28⸱10-5 and 0.72⸱10-5 cm2·s-1 at temperature of 753 and 823 K for each melt, respectively. 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.

Reduction of ZrO 2 by lithium during electrolysis of LiCl-KCl-Li 2 O melt at 650°C was studied using a set of physicochemical methods of analysis. Influence of ZrO 2 in the space near a molybdenum cathode on the kinetics of the cathode process was established. Possible variations of the electrode reaction associated with the zirconium reduction were proposed. The appearance of ZrO 2 in the cathode space resulted in consumption of reduced lithium and in increase in the potential relaxation time of the molybdenum cathode after cathode polarization. Long-term galvanic impulse electrolysis of LiCl-KCl-Li 2 O melt at 650°C was carried out using the molybdenum cathode which was immersed into the ZrO 2 powder. According to the X-ray fluorescence analysis as well as the method of nuclear reactions the reduction product was presented by the ZrO 2 , Li 2 ZrO 3 , Zr 3 O phases. Additionally, by alloying the reduction product with tin, the ZrO 2 reduction degree to metallic zirconium was estimated, which was close to zero. It was assumed that the main pathway for the appearance of the metallic zirconium in the ZrO 2 reduction product during electrolysis of the LiCl-KCl-Li 2 O melt was direct electroreduction of dissolved zirconium in the melt.