Melt-spun calcium disilicide and its exfoliation performance
Journal
Journal of Materials Research and Technology
Journal Volume
39
Start Page
2877
End Page
2887
ISSN
22387854
Date Issued
2025-11
Author(s)
Abstract
Silicon nanosheets (SiNS) have garnered significant interest due to their high surface area and tunable electronic properties. Calcium disilicide (CaSi2), a layered Zintl phase, serves as a promising precursor for SiNS, but commercial CaSi2 is often plagued by impurities that hinder exfoliation. This study reports a melt-spinning synthesis method to produce CaSi2 with controlled stoichiometry (Ca1+xSi2, x = 0, 0.05, 0.10), aiming to improve phase purity and exfoliation performance. Ex-situ analyses suggest that Ca-rich phases contribute to disrupting the layered structure and facilitating decalcification. Post-annealing, the materials were exfoliated using CuCl2 and characterized by SEM, XRD, BET, and particle size analysis. The SiNS derived from Ca1.10Si2 demonstrated the highest exfoliation efficiency, exhibiting a well-defined lamellar structure in SEM, excellent suspension stability, and the largest pore-volume fraction—substantially exceeding those of Ca1.05Si2 and Ca1.00Si2-thereby confirming enhanced exfoliation in the Ca-rich composition, ultimately forming amorphous SiOx with no detectable bulk silicon in the excess-calcium composition through XRD. These findings highlight the potential of melt-spun CaSi2 as a scalable precursor for high-quality 2D silicon materials. Given their large surface area and structural tunability, the obtained silicon nanosheets are promising for applications in electronics, optoelectronics, and sustainable energy conversion technologies.
Subjects
Calcium disilicide
Decalcification
Exfoliation
Melt-spinning
Silicon nanosheets
SDGs
Publisher
Elsevier Editora Ltda
Type
journal article