Electrodeposition of Silicon from the KCl–CsCl–K2SiF6 Melt

—Silicon and its composites are widely used to manufacture new electrochemical devices for energy conversion and storage. Current research is being actively conducted and aimed at developing methods for the preparation of micro- and nanosized silicon from molten salts. Therefore, the basic regularities of silicon electrodeposition on glassy carbon from the KCl–CsCl–K 2 SiF 6 melt at a temperature of 690°C are studied by cyclic chronovoltammetry and square-wave voltammetry. The electroreduction of silicon ions on glassy carbon under experimental conditions is shown to proceed in one electrochemically reversible four-electron stage. The formal kinetic parameters of the electroreduction of silicon ions under the nonstationary polarization conditions are determined. The diffusion coefficient of electroactive silicon ions is estimated by the Berzins–Delahay equation for an electrochemically reversible process and is equal to 2.75 × 10 –5 cm 2 /s. Silicon is electrodeposited on glassy carbon in the galvanostatic mode at a cathodic current density of 25 and 50 mA/cm 2 . As a result, deposits of fibrous morphology with the average diameter from 0.12 to 0.80 μm are formed.