From Highly Purified Boron Nitride to Boron Nitride‐Based Heterostructures: An Inorganic Precursor‐Based Strategy

The current approaches used to fabricate hexagonal boron nitrides (h‐BN) from boron trioxide and urea always results in contamination of the h‐BN product with carbon/oxygen. Thus, discovering a facile way of mass producing high‐purity h‐BN remains a challenge. A simple yet highly efficient thermal treatment approach to large‐scale fabrication of nanoporous h‐BN with high yield, high purity, and high crystallinity is described using NaNH2 and NaBH4 as the oxygen‐ and carbon‐free precursors. The unique properties of inorganic metal salts, i.e., high melting point and strong electrostatic interaction with carbon substrates, render this strategy suitable for the production of homogeneous h‐BN/mesoporous carbon and h‐BN/carbon nanotube heterostructures of high crystallinity, high h‐BN dispersity, and with a strong interfacial effect. These unique features make them promising candidates for supercapacitor applications, resulting a significantly enhanced specific capacitance. This study provides new insight into the fabrication of high‐purity h‐BN and h‐BN‐based heterostructures thus expanding their application in the field of energy storage and transformation. A simple yet highly efficient approach is developed for the fabrication of high‐purity, crystalline, nanoporous hexagonal boron nitrides (h‐BN) from inorganic starting materials. h‐BN/carbon heterostructures exhibiting improved supercapacitive behavior are also created.