Universal Mild Exfoliation of Large-Size Two-Dimensional Materials for Thermal Interface Composites

The large-scale production of high-quality two-dimensional (2D) materials remains challenging without organic solvents or harsh treatments. The study presents a green, universal approach using one-step ultrasonic exfoliation in liquid nitrogen (UEILN) to produce 2D materials with large lateral sizes, high yields, and good quality. Using h-BN as an example, we highlight the critical control of vibrational energy from gaseous nitrogen situated between interlayer exfoliation and intralayer bonding energies. This method avoids structural damage and is successfully applied to graphite, MoS 2, and WS 2 . The resulting h-BN/poly(vinyl alcohol) composite film exhibits a thermal diffusion coefficient of 6.4 mm 2 ·s –1, tensile strength of 31.8 MPa, compressive strength of 78.8 MPa, flame retardancy, and enhanced dielectric properties. This work offers an eco-friendly route for scalable 2D material production and advances their practical applications.