Scalable Synthesis of 2D Si Nanosheets

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 largescale fabrication of 2D Si remains challenging. This study reports a roomtemperature and one-step synthesis technique that leads to large-scale and low-cost production of Si nanosheets (SiNSs) with thickness approximate to 4 nm and lateral size of several micrometers, based on the intrinsic delithiation process of chemically leaching lithium from the Li13Si4 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 delithiationinduced 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.