Synthesis of crystalline Si-based nanosheets by extraction of Ca from CaSi₂in inositol hexakisphosphate solution

Abstract

Crystalline Si-based nanosheets were successfully synthesized from CaSi2 by a simple soft chemical synthetic method in solution. By immersing CaSi2 powder or CaSi2/Si substrates in an inositol hexakisphosphate (IP6) solution, Ca atoms were extracted from the CaSi2 particles, then Si-based nanosheets were formed. The morphological, structural and optical properties of the Si-based nanosheets were investigated. It is noted that the thin Si-based nanosheets stacked with a void space formed bundle structures, and the nanosheets were easily exfoliated from the bundles to expose the surfaces corresponding to the Si{111} planes. Meanwhile, the surface of the Si nanosheets might be terminated by O, H, or OH bonds. The Si-based nanosheet bundles were then formed and directly rooted to the Si(111) substrates, and had a remarkably highly symmetrical morphology. This study demonstrated a simple method for preparing Si-based nanosheets, and electro- and photo-chemical applications would possibly be expected, such as in lithium ion batteries.

Silicene, Siloxene, or Silicane? Revealing the Structure and Optical Properties of Silicon Nanosheets Derived from Calcium Disilicide

“…Si-NSs exhibit Raman modes at 375 (2D-Si planes), 35,47,48 489 (2D-Si6 rings), 35,47 632 (SiHn), 47,49 726 (SiH), 50 ~900 (SiH2 and/or SiOH), 2126 (SiHn), [49][50][51] and 2248 cm -1 (OSiHn). 52 The peak at 375 cm -1 is likely Si-Si vibrations, which also exist in CaSi2 at 387 cm -1 ; 35,47,48 this is confirmed by DFT (see attached GIF files in the Supporting Information for visualization of the vibrational modes). The peaks at 375 and 489 cm -1 are red-shifted compared to CaSi2, which is characteristic of phonon confinement effects that result from increased sheet separation.…”

Recent Advances in Silicon‐Based Electrodes: From Fundamental Research toward Practical Applications

“…2D Nanosheets: 2D nanostructured Si-based materials have emerged as candidates for anodes with improved electrochemical performance due to their intrinsic fast ionic/electronic diffusion kinetics. [190,191] 2D Si-based materials are divided into three main classes: nanosheets, silicene, and thin films. 2D Si nanosheets are typically synthesized using a combination of exfoliation and reduction techniques.…”

Scalable and Physical Synthesis of 2D Silicon from Bulk Layered Alloy for Lithium-Ion Batteries and Lithium Metal Batteries

“…The obtained carbon coating Si nanosheets presented a high capacity of 865 mAh g –1 after 500 cycles at 1 A g –1 . In addition, other chemical synthetic strategies, such as chemical extraction, topochemical reaction, liquid oxidation, and exfoliation, as well as chemical dealloying at low, room, and high temperature, − ,, are also designed to produce 2DSi from the CaSi 2 precursor. Obviously, the above synthetic methods are complicated, and some of them may pollute the environment.…”