An exploration on the form factors of turbulence kinetic energy transfer for shear exfoliation of graphene.

Producing defect-free and large-lateral-size 2D materials via cost-effective methods is important for mass application. Recently, shear exfoliation showed great promise for large-scale production due to its simple operation, environmental-benignity, and wide adaptability. However, a long-standing challenge is that with more nanosheets produced, a ceiling yield and shattered products are encountered, which significantly limit their wider application. The way and efficiency of energy transfer in fluid is undoubtedly the key point in determining the exfoliation efficiency, yet there has no in-deep mechanism elucidation so far. Thus, a thorough investigation regarding the turbulence energy transfer is critically necessary. Herein, we identify two main factors which critically determine the exfoliation yield and provide a statistical analysis on the relationship between these factors and exfoliation yield. In the initial shearing process, the coexistence of the 2D nanosheets and raw particles is the dominant factor; with time passes by, the dimensional change of raw materials gradually shows more influence on the energy transfer. These factors together lead to attenuated efficiency and a power function relationship between yield and exfoliation time. This investigation gives a statistical explanation regarding shear exfoliation technology for 2D materials preparation and provides valuable insights for mechanical exfoliating high-quality 2D materials.