Cold sintering of Van Der Waals layered compounds

Abstract

Van der Waals (vdW) layered materials have a wide range of applications and their bulks are commonly prepared using energy intensive pressure assisted sintering. For example, in the case of graphite or boron nitride temperatures in excess of 2000 °C are required. In this work, for the first time, we demonstrated that most of the vdW layered materials (i.e., Graphite, h-BN, Bi2Te3, MoS2, WS2 and SnS2) can be consolidated at room temperature under an uniaxial pressure ranging between 100 and 800 MPa. The consolidation is driven interplanar slipping, while inter-flake adhesion relies on the formation of vdW bonds. Large flakes exceeding 100 μm in size results in improved consolidation due to their high tap density (in the range of 70–80% of the relative density) and facilitated interplanar slipping under the applied uniaxial pressure. Despite its obvious advantages, the cold sintering of vdW layered compounds remains unexplored and this work is an initial attempt to generalize its feasibility.