Structural Control and Ultra-High-Speed Synthesis of hBN Nanosheets on Nickel Substrates Using a Sputtering-Annealing Hybrid Process

Hexagonal boron nitride (hBN) is a two-dimensional material with exceptional thermal stability, electrical insulation, and optical properties, making it highly promising for applications in electronics, optics, and catalysis. However, the efficient large-scale synthesis of high-quality hBN remains challenging. This study investigates the synthesis of hBN nanosheets on nickel substrates using the Sputtering Annealing Hybrid Process (SAHP), which combines magnetron sputtering and high-temperature annealing. The nickel substrate’s thermal treatment facilitated surface smoothening, larger grain sizes, and step-edge formation, promoting oriented growth. High-purity, highly oriented, and well-aligned hBN thin films were synthesized at 1200 °C, exhibiting strong c -axis orientation as confirmed by electron diffraction and Raman spectroscopy. Nickel substrates demonstrated superior high-temperature stability and atomic adsorption efficiency compared to copper, enhancing the crystallinity and uniformity of the hBN films. Furthermore, Nafion/hBN composite membranes tested in fuel cells achieved a peak power density of 0.66 mW/cm 2, outperforming Nafion alone (0.56 mW/cm 2 ), due to hBN’s gas barrier properties that reduced hydrogen crossover and improved efficiency. The synthesized hBN nanosheets exhibited high crystallinity, structural stability, and excellent performance in both electronic and energy applications. These findings highlight the SAHP method’s potential for scalable, high-quality hBN synthesis and its role in advancing next-generation fuel cell and electronic device technologies.