Independent thickness and lateral size sorting of two-dimensional materials

Abstract

Two-dimensional (2D) materials possess unique thickness-and lateral-size-dependent properties. Many efforts have been devoted to obtaining 2D materials with narrow structure heterogeneity while it is still challenging to independently control their thickness and lateral size, limiting their widespread applications. Here, we develop a three-step method which achieves independent thickness and lateral size sorting of 2D materials. Taking 2D h-BN flakes as an example, their thickness and lateral size are independently sorted to different fractions with thicknesses smaller than 6 nm. In addition, the 2D h-BN flakes possess narrow distributions of both thickness and lateral size. We further develop a force field extraction method and achieve scalable size sorting of 2D h-BN, which is universal for sorting other 2D materials including MoS 2 and graphene oxide. This work reports an effective method to produce structure homogenous 2D materials and will help fundamental studies and applications of 2D materials where thickness and lateral size are of concern.

Stabilized Solid Electrolyte Interphase Induced by Ultrathin Boron Nitride Membranes for Safe Lithium Metal Batteries

“…To achieve this goal, some functional materials, such as alumina nanoparticles, − graphene, molybdenum disulfide (MoS 2 ), and hexagonal boron nitride (h-BN) − are used to construct the coating layer. Among these materials, h-BN provides an ultrahigh thermal conductivity (∼400 W m –1 K –1 ), high mechanical strength (elastic constant of 220–510 N m –1 with thicknesses of 1–2 nm), and good electrolyte wettability, making it an ideal material to supplement the separator. , …”

“…Among these materials, h-BN provides an ultrahigh thermal conductivity (∼400 W m −1 K −1 ), high mechanical strength (elastic constant of 220−510 N m −1 with thicknesses of 1−2 nm), and good electrolyte wettability, making it an ideal material to supplement the separator. 20,21 In addition to blocking the lithium dendrite growth, constructing a stable solid electrolyte interphase (SEI) layer is another necessary strategy to restrict lithium dendrite growth, which further guarantees the safety of LIBs. 22−24 It has been widely recognized that organic SEI components (such as ROLi and ROCO 2 Li, where R represents an organic group) are unstable and soluble in the electrolyte, while inorganic SEI components (such as LiF, Li 2 O, and Li 3 N), which are formed by the reaction of F, O, and N-containing groups in the electrolyte with Li, are stable and provide acceptable ionic conductivity.…”

Methods of hexagonal boron nitride exfoliation and its functionalization: covalent and non-covalent approaches

“…Based on this method, exfoliated h-BN with different thicknesses and lateral sizes is individually sorted into diverse fractions, obtaining 2D h-BN flakes with a thickness of less than 6 nm. 160 …”

Centrifuge‐Free Separation of Solution‐Exfoliated 2D Nanosheets via Cross‐Flow Filtration

“…Examples include chromatography, field-flow fractionation, force-field extraction, magnetic separation, microfiltration, and ultrafiltration. [20][21][22][23][24][25] Among these methods, microfiltration (MF) and ultrafiltration (UF) are particularly attractive for solid/liquid separation due to their relative simplicity and energy efficiency. However, conventional dead-end filtration processes (e.g., vacuum filtration) are susceptible to fouling because solid material accumulates on the filter surface.…”