Electrochemical Control of Concentration of Silicon Ions during Electrolysis of Molten Electrolytes

Abstract Silicon and silicon-based materials are increasingly used, as this element is in demand in microelectronics, solar energy, as well as in lithium-ion batteries with improved anode capacity. To obtain silicon of the required morphology and dimensions, electrodeposition methods are promising. At the same time, in order to meet the requirements, electrodeposition should be performed at a stable concentration of silicon ions in electrolytes. In the present work possible ways are briefly discussed, and a method of electrochemical control of concentration of silicon ions during electrolysis of melts based on mixtures of LiCl, KCl, CsCl with the addition of K2SiF6 in the range of operating temperatures from 550 to 790°C is proposed and tested. For three electrolyte compositions, empirical dependences of the current density of the electroreduction peak current of silicon ions as a function of their concentration in the melts were plotted using spectral analysis, voltametric measurements, and an electrochemical sensor. Based on the obtained dependences, the possibility of online control of silicon ion concentration during electrolysis of KCl-K2SiF6 melt was demonstrated.