Yttria-Stabilized Zirconia Assisted Green Electrochemical Preparation of Silicon from Solid Silica in Calcium Chloride Melt

Li, Guangqiang; Chen, George Z.; Qin, Qingwei; Gao, Yunming; Huang, Zhenbiao; He, Lin

Abstract

A novel integrated cell with O2-|YSZ|Pt|O2(air) reference and counter electrodes was constructed using a short yttria-stabilized zirconia solid electrolyte (YSZ) tube. Combining with cyclic voltammetry and potentiostatic electrolysis methods, green electrochemical preparation of Si from solid SiO2 in CaCl2 melt at 1173 K was studied via an experimental apparatus containing the novel integrated cell under completely carbon-free conditions; the effect of electrolysis time on the morphology of the Si product was also investigated by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS). The results show that the morphology of the product obtained from potentiostatic electrolysis at a low overpotential (− 1.6 V) undergoes an evolution from SiO2 raw powder with different sizes to aggregates of spherical particles and small particles with partial reduction, and then to Si nuclei, and finally to Si wires or flakes. The morphology of electrolytic products has little relation with that of SiO2 raw powder and may be controlled by applying different potentials. Furthermore, the longer the electrolysis time, the more the Si wires grow, and the higher the Si purity overall. It is feasible that the experimental apparatus without the sealed stainless steel reactor and any carbonaceous materials can be used to prepare Si from solid SiO2 in CaCl2 melt and release O2 gas at the same time.

Citation

Li, G., Chen, G. Z., Qin, Q., Gao, Y., Huang, Z., & He, L. (2021). Yttria-Stabilized Zirconia Assisted Green Electrochemical Preparation of Silicon from Solid Silica in Calcium Chloride Melt. Metallurgical and Materials Transactions B, 52, 1708-1715. https://doi.org/10.1007/s11663-021-02138-1

• Journal Article Type: Article
• Acceptance Date: Feb 26, 2021
• Online Publication Date: Mar 31, 2021
• Publication Date: Jun 1, 2021
• Deposit Date: Apr 9, 2021
• Publicly Available Date: Apr 1, 2022
• Journal: Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
• Print ISSN: 1073-5615
• Electronic ISSN: 1543-1916
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 52
• Pages: 1708-1715
• DOI: https://doi.org/10.1007/s11663-021-02138-1
• Keywords: Silica, Silicon, Calcium chloride, Green electrolysis, Zirconia solid electrolyte.
• Public URL: https://nottingham-repository.worktribe.com/output/5437160
• Publisher URL: https://link.springer.com/article/10.1007/s11663-021-02138-1
• Additional Information: This is a post-peer-review, pre-copyedit version of an article published in Metallurgical and Materials Transactions B. The final authenticated version is available online at: http://dx.doi.org/10.1007/s11663-021-02138-1