Suzuki Yuta, Nozaki Saya, Tanaka Seiya, Goto Takuya
Harris Science Research Institute, Doshisha University, Kyotanabe, Kyoto 610-0394, Japan.
Department of Science of Environment and Mathematical Modeling, Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0394, Japan.
Inorg Chem. 2024 Jan 8;63(1):203-210. doi: 10.1021/acs.inorgchem.3c03023. Epub 2023 Dec 19.
The formation of Si(II) by the comproportionation reaction between electrodeposited silicon and Si(IV) ions [Si(IV) + Si ⇄ 2Si(II)] in fluoride melts has been discussed in many previous reports on the electrochemical processing of silicon. In this study, the coordination structure of Si(II) ions in LiF-KF, LiF-NaF, NaF-KF, and LiF-NaF-KF melts was investigated by high-temperature Raman spectroscopy and quantum chemical calculation based on density functional theory. The formation of Si(II) ions was induced by mixing metallic silicon powder as the source of Si, with the melts containing hexafluoro silicate or silicon dioxide as the source of Si(IV) ions. The simulated vibrational modes of the Si(II) species and the experimental Raman bands showed good agreement. It was found that both Si(II) and Si(IV) species were detected in either fluoride melt, demonstrating that the proposed comproportionation reaction between Si and Si(IV) occurred. In addition, the interaction between Si(II) and F, O, Li, Na, and K ions significantly changed depending on the composition of fluoride melts. The coordination structure of the Si(II) ions reported in this study will provide clues for controlling the electrodeposition process of silicon in fluoride melts.
在许多先前关于硅的电化学加工的报告中，已经讨论了在氟化物熔体中通过电沉积硅与Si(IV)离子之间的歧化反应[Si(IV)+Si⇄2Si(II)]形成Si(II)的情况。在本研究中，通过基于密度泛函理论的高温拉曼光谱和量子化学计算，研究了LiF-KF、LiF-NaF、NaF-KF和LiF-NaF-KF熔体中Si(II)离子的配位结构。通过将金属硅粉作为Si源与含有六氟硅酸盐或二氧化硅作为Si(IV)离子源的熔体混合来诱导Si(II)离子的形成。Si(II)物种的模拟振动模式与实验拉曼谱带显示出良好的一致性。发现在任何一种氟化物熔体中都检测到了Si(II)和Si(IV)物种，这表明所提出的Si与Si(IV)之间的歧化反应发生了。此外，Si(II)与F、O、Li、Na和K离子之间的相互作用根据氟化物熔体的组成而显著变化。本研究报道的Si(II)离子的配位结构将为控制氟化物熔体中硅的电沉积过程提供线索。
