Mass production of 2D materials by intermediate-assisted grinding exfoliation

Abstract

The scalable and high-efficiency production of 2D materials is a prerequisite to their commercial use. Currently, only graphene and graphene oxide can be produced on a ton scale, and the inability to produce other 2D materials on such a large scale hinders their technological applications. Here we report a grinding exfoliation method that uses micro-particles as force intermediates to resolve applied compressive forces into a multitude of small shear forces, inducing the highly efficient exfoliation of layer materials. The method, referred to as intermediate-assisted grinding exfoliation (iMAGE), can be used for the large-scale production of many 2D materials. As an example, we have exfoliated bulk h-BN into 2D h-BN with large flake sizes, high quality and structural integrity, with a high exfoliation yield of 67%, a high production rate of 0.3 g h−1 and a low energy consumption of 3.01 × 106 J g−1. The production rate and energy consumption are one to two orders of magnitude better than previous results. Besides h-BN, this iMAGE technology has been used to exfoliate various layer materials such as graphite, black phosphorus, transition metal dichalcogenides, and metal oxides, proving its universality. Molybdenite concentrate, a natural low-cost and abundant mineral, was used as a demo for the large-scale exfoliation production of 2D MoS2 flakes. Our work indicates the huge potential of the iMAGE method to produce large amounts of various 2D materials, which paves the way for their commercial application.

High-throughput production of cheap mineral-based two-dimensional electrocatalysts for high-current-density hydrogen evolution

“…In brief, 2D MoS 2 was first prepared by exfoliating bulk MoS 2 (Supplementary Fig. 2 ) by an interMediate-Assisted Grinding Exfoliation (iMAGE) technique that was able to obtain 2D materials at the tonne scale 28 . Here we used a modified iMAGE technique that used Mo 2 C as the force intermediary to facilitate the exfoliation of MoS 2 because it has a low electrical resistivity (57 μΩ cm) and a high hardness (Moh’s hardness is 7) 29 .…”

“…All chemicals were used as received without further purification. The 2D MoS 2 was exfoliated by modifying a method previously reported 28 . The bulk MoS 2 (10 g, with an average particle size of 1–2 μm) and the Mo 2 C (20 g, with an average particle size of 44 μm) powders were mixed together and added into a rotational grinding apparatus (Retsch RM 200, Germany).…”

Giant magneto-birefringence effect and tuneable colouration of 2D crystal suspensions

“…To prepare CTO monolayers, we followed a four-stage approach (Supplementary Fig. 1a ), similar to previously reported but with some changes 32 , 33 . In stage I, TiO 2 (0.25 mol, 20 g), CoO (0.03 mol, 2.25 g), K 2 CO 3 (0.06 mol, 5.94 g) and Li 2 CO 3 (0.01 mol, 0.67 g), all from Shanghai Aladdin Biochemical Co., Ltd., China, were mixed in a stoichiometric ratio by grinding in a corundum crucible and annealed at 1000 °C for 5 h. The obtained mixture was ground again at room temperature, followed by a second annealing at 1000 °C for 20 h. The resulting compound K 0.8 Ti (5.2− y )/3 Li (0.8−2 y )/3 Co y O 4 has a layered crystal structure and good crystallinity (Supplementary Fig.…”

Magneto‐optic effect of two‐dimensional materials and related applications

“…[ 19 ] Typically, most of layered materials have strong intralayer bonding while weak van der Waals forces between layers, enabling the facile preparation of 2D materials from the layered bulk by exfoliation. [ 20 ] Meanwhile, chemical vapor deposition (CVD) are widely used to synthesize high‐quality 2D crystals. So far, the bandgaps of 2D materials have covered a wide range, [ 20 ] and that the family of 2D materials contains insulating, semiconducting and metallic materials.…”