Near-room-temperature water-mediated densification of bulk van der Waals materials from their nanosheets

JY Zhu and F Li and YZ Hou and H Li and DX Xu and JY Tan and JH Du and SG Wang and ZB Liu and HA Wu and FC Wang and Y Su and HM Cheng, NATURE MATERIALS, 23 (2024).

DOI: 10.1038/s41563-024-01840-0

The conventional fabrication of bulk van der Waals (vdW) materials requires a temperature above 1,000 degrees C to sinter from the corresponding particulates. Here we report the near-room-temperature densification (for example, similar to 45 degrees C for 10 min) of two- dimensional nanosheets to form strong bulk materials with a porosity of <0.1%, which are mechanically stronger than the conventionally made ones. The mechanistic study shows that the water-mediated activation of van der Waals interactions accounts for the strong and dense bulk materials. Initially, water adsorbed on two-dimensional nanosheets lubricates and promotes alignment. The subsequent extrusion closes the gaps between the aligned nanosheets and densifies them into strong bulk materials. Water extrusion also generates stresses that increase with moulding temperature, and too high a temperature causes intersheet misalignment; therefore, a near-room-temperature moulding process is favoured. This technique provides an energy-efficient alternative to design a wide range of dense bulk van der Waals materials with tailored compositions and properties.

Return to Publications page