Electrolytic production of silicon using liquid zinc alloy in molten CaCl2

Kouji Yasuda, Takeyuki Shimao, Rika Hagiwara, Takayuki Homma, Toshiyuki Nohira

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    A new electrolytic production process for solar-grade Si has been proposed utilizing liquid Si–Zn alloy cathode in molten CaCl2. To establish this process, the behavior of liquid Zn metal in molten CaCl2 at 1123 K was investigated. Evaporation of Zn metal was largely suppressed by immersion in the molten salt, which enabled the use of a Zn electrode despite its high vapor pressure. Cyclic voltammetry results suggested that the reduction of SiO2 on a Zn cathode proceeded at a more negative than 1.45 V vs. Ca2+/Ca. After potentiostatic electrolysis at 0.9 V, Si particles with sizes of 2–30 μm were precipitated in the solidified Zn matrix by a slow cooling process. The rate-determining step for electrochemical reduction of SiO2 on the Zn cathode was discussed on the basis of a measurement of the alloying rate between solid Si and liquid Zn.

    Original languageEnglish
    Pages (from-to)H5049-H5056
    JournalJournal of the Electrochemical Society
    Volume164
    Issue number8
    DOIs
    Publication statusPublished - 2017 Jan 1

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Renewable Energy, Sustainability and the Environment
    • Surfaces, Coatings and Films
    • Electrochemistry
    • Materials Chemistry

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