Progress on preparation and microstructure tailoring of two-dimensional silicon nanosheets and applications

Advances in energy technologies and materials have underscored the critical importance of preparing and modifying electrochemical energy storage materials, with nanomaterials playing an increasingly prominent role. Among these, two-dimensional silicon (2D-Si) nanomaterials have garnered significant attention as a research focus. Various methods for synthesizing silicon nanosheets have been developed, including "top-down" techniques such as exfoliation of layered silicides, delithiation of lithium-silicon alloys, and liquid-phase exfoliation, as well as "bottom-up" approaches like epitaxial growth, chemical vapor deposition, and magnesiothermic reduction. These techniques facilitate the controllable fabrication of silicon nanosheets, enabling their application in diverse fields such as electrochemical lithium storage and photocatalysis. This review provides an overview of the fundamental structure and physicochemical properties of 2D silicon nanosheets. It highlights that multilayered silicon nanosheets, characterized by a higher number of atomic layers, exhibit enhanced structural stability due to the reduced presence of unsaturated atoms. However, their surface atoms remain vulnerable to oxidation. Strategies such as surface hydrogenation and functionalization with organic groups can effectively passivate the nanosheet surfaces, mitigating the detrimental effects of oxidation on their physicochemical properties. Additionally, this review summarizes the characteristics and applications of various preparation methods for 2D silicon nanosheets and outlines potential directions for future research.