Self-Toughened 2D Moiré Superlattice Membranes with Extreme Thermal Shock Tolerance.

Excellent mechanical strength and toughness are demanded for two-dimensional material (2DM) membranes in various applications to withstand extreme strain and temperature changes and resist crack propagation. However, the trade-off between strength and toughness poses significant challenges in meeting these requirements. This study presents a self-toughened 2D moiré superlattice membrane composed of vertically stacked hexagonal boron nitride and graphene (hBN/Gr) that exhibits high mechanical strength. The intrinsic toughness originates from the high energy release rate associated with the crack deflection and bifurcation in hBN. Remarkably, this robust membrane endures 200 cycles of thermal shock up to 1800 K with 10 K s heating rate, during which high-entropy alloy nanoparticles (HEA-NPs) are successfully synthesized. The findings pave the way for the design and fabrication of robust 2D superlattices, facilitating future exploration under extreme conditions.