Electrowinning of Silicon from K 2SiF6 ‐ Molten Fluoride Systems

The electrowinning of silicon from solutions of in fluoride melts at 745°C has been achieved. Electrolysis close to the deposition potential gave dense, coherent, and well‐adherent deposits. Up to 3 mm thick films were grown using a concentration of 4–6 m/o. The polycrystalline silicon has a columnar structure with grain size up to 100 μm. The morphology of the electrodeposited silicon onto silver substrates and its dependence on the deposition parameters is discussed. The purity of the deposits is substantially higher than that previously reported for electrodeposited silicon.