Silicon Electrodeposition from Low-Melting LiCl–KCl–CsCl Melts
O. B. Pavlenko, Yu. A. Ustinova, С. И. Жук, А. V. Suzdaltsev, Yu. P. Zaikov
Abstract
The possibility of silicon electrodeposition using LiCl–KCl–CsCl–LiF–K2SiF6 and LiCl–KCl–CsCl–K2SiF6 electrolytes is investigated. The kinetics of silicon electrowinning on glassy carbon at a temperature of 480–550°C is studied by voltammetry. Silicon electrodeposition under experimental conditions is found to proceed in one four-electron stage and to be not electrochemically reversible. The results of electrochemical measurements are used to estimate the diffusion coefficients of silicon ions in LiCl–KCl–CsCl melts (3.2 × 10–5, 7.2 × 10–6 cm2/s at temperatures of 480, 550°C, respectively) and select conditions for silicon electrodeposition. The structure and morphology of the silicon deposits formed under potentiostatic conditions are investigated. A decrease in the lithium chloride concentration in the melt is shown to result in silicon deposits in the form of dendrites and fibers.