Scalable exfoliation of h-BN into boron nitride nanosheets by molten salt-assisted thermal treatment in air

Boron nitride nanosheets (BNNSs) are expected to be high-efficiency thermal conducting fillers or mechanical reinforcements in advanced composites. However, the scalable preparation of ultrathin BNNSs with high crystallinity is still a challenge limiting their applications. In this work, a simple and scalable strategy is developed to exfoliate h-BN into BNNSs by molten salt-assisted thermal treatment in air. Ultrathin BNNSs with large lateral sizes and low defect density are successfully obtained.