Electrodeposition of Si in molten CaCl2 above 1300K

Aiming at direct electrodeposition of liquid metallic Si in molten CaCl2, electrodeposition of metallic Si has been attempted at 1373 similar to 1573K. In molten CaCl2 containing CaSiO3 as Si source, the electrochemical behavior was investigated by cyclic voltammetry. Cathodic current increased with the increase in added amount of CaSiO3, which indicates that the electrochemical reduction of a Si ion occurred in the bath. The results by cyclic voltammetry suggest that the solubility of CaSiO3 enlarged with the temperature increase, and was about 7 mol% at 1573 K. Metallic Si was obtained by potentiostatic electrolysis. However, the total amount of metallic Si was still insufficient, and undesirable reactions, such as CaSi2 formation and MoSi2 formation, could not be controlled. To perform better electrolysis, the influence of the type of calcium silicate on Si deposition should be investigated. Suitable cathode material for metallic Si deposition is also a subject to consider.