Electrodeposition of Silicon from the Low-Melting LiCl-KCl-CsCl-K2SiF6Electrolytes

Abstract

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 coefficient calculated by the Matsuda-Ayabe equation was 0.72·10-5 cm2·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. © 2022 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BYNC- ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: permissions@ioppublishing.org. [DOI: 10.1149/1945-7111/ac5a1c].