Scalable Synthesis of 2D Si Nanosheets

Abstract

2D Si nanomaterials have attracted tremendous attention due to their novel properties and a wide range of potential applications from electronic devices to energy storage and conversion. However, high-quality and large-scale fabrication of 2D Si remains challenging. This study reports a room-temperature and one-step synthesis technique that leads to large-scale and low-cost production of Si nanosheets (SiNSs) with thickness ≈4 nm and lateral size of several micrometers, based on the intrinsic delithiation process of chemically leaching lithium from the Li Si alloy. Together with experimental results, a combination of theoretical modeling and atomistic simulations indicates that the formation of single SiNS arises from spontaneous delamination of nanosheets from their substrate due to delithiation-induced mismatch. Subsequently, the synthesized Si nanosheets evolve from amorphous to nanocrystalline to crystalline structures during annealing at different temperatures. It is demonstrated that these SiNSs possess unique mechanical properties, in particular ultralow friction, in contrast to their bulk counterparts.

Scalable 2D Mesoporous Silicon Nanosheets for High‐Performance Lithium‐Ion Battery Anode

“…Among these approaches, chemical exfoliation is an effective method to produce single‐ and multilayer nanosheets, involving acid etching or ion exchange of interlayer metal ions with protons. These methods generally suffer from complicated process and high‐cost or unstable precursors (like Si 6 H 6 , CaSi 2 , and Li 13 Si 4 ), limiting their useful applications. Although CVD has been extensively used to yield various 2D materials, the method depending on suitable epitaxial substrate undergoes high cost and low productivity, which restricts its commercial application for lithium‐ion batteries .…”

Mechanical mismatch-driven rippling in carbon-coated silicon sheets for stress-resilient battery anodes

“…Similarly, Si thin film has long been considered as a suitable electrode configuration except for its low loading density, poor electric conductivity (~10 −4 S m −1 ), and absence of binders 6 , 26 . Recently, several synthetic methods for 2D Si have been established (e.g., chemical vapor deposition (CVD) 27 , templated coating method 28 , molten salt-induced exfoliation 14 , and exfoliation of lithiated Si 29 ) and showed the promise of achieving high-energy-density LIBs. These studies call for fundamental understanding in stress evolution and chemomechanical degradation toward optimized performance of 2D Si.…”

Solution‐Processed Silicane Field‐Effect Transistor: Operation Due to Stacking Defects on the Channel

“…Silicanes were prepared according to a previously reported liquid exfoliating method, [ 19,20 ] and the obtained sheets were transferred to silicon substrates covered with 300‐nm‐thick SiO 2 . Although single‐layered silicene is a buckled sp 2 /sp 3 metastable lattice of silicon, [ 18 ] silicane is composed of Si‐sp 3 saturated bonds, thereby, it is relatively stable to air exposure during the course of the atomic‐force microscopy (AFM) and Raman analyses.…”