Hexagonal Boron Nitride Nanosheets via Salt‐Assisted Strategies

Two‐dimensional (2D) hexagonal boron nitride nanosheets (h‐BNNSs) are versatile platforms for thermal, mechanical, and catalytic applications. However, scalable preparation that preserves both structural integrity and economic feasibility is still a major bottleneck. Herein, we review the progress in the versatility of salt‐assisted preparation and modification of h‐BNNS, where ionic compounds enable a controllable physicochemical environment for material engineering. In bottom‐up synthesis, the molten salt medium enhances mass transfer and lowers reaction barriers, promoting controlled crystal growth. In top‐down exfoliation, ion intercalation overcomes the interlayer van der Waals force to enable efficient production of high‐quality nanosheets. Meanwhile, the chemically active ionic environment bridges preparation and modification, allowing elemental doping, interface engineering, and nanoparticle loading to tailor properties and expand applications. Finally, we summarize key bottlenecks and outline future directions toward scalable, controllable, and application‐oriented salt‐assisted h‐BNNS engineering.