Visualizing Nucleation and Growth Process of Vanadium‐Supramolecular Nanoribbons Self‐Assembled by Rapid Cooling Method towards High‐Capacity Vanadium Nitride Anode Materials

Abstract The vanadium‐supramolecules and their derivatives are in high demand because of their huge potential applications in various fields, especially as electrodes for supercapacitors and batteries. However, the complex synthesis process is still a significant challenge. Furthermore, for these self‐assembly processes, the early reaction stages, intermediates, and details of reaction kinetics are still unknown. Here, an efficient approach of rapid cooling for large‐scale fabrication of melamine‐ammonium metavanadate (C₃H₆N₆‐NH₄VO₃) supramolecular nanoribbons is reported, and the corresponding nucleation and growth process are visualized by using an in situ polarizing microscope. The thermally induced nucleation takes place within tens of seconds, and once the nucleus is formed, C₃H₆N₆ and NH₄VO₃ begin to assemble into nanoribbons under thermal control and grow epitaxial around the already‐formed nuclei. The growth process is much slower than the nucleation, until all small molecules are consumed. Rapid heat induction (rapid cooling) and shear force induction (stirring) help to form a uniform and wider 2D sheet rather than fibers or ribbons. After pyrolysis, the vanadium‐supramolecules derived vanadium nitride (VN)/carbon nanoribbons present a mesoporous structure, which endows the VN/carbon with high capacitance of 266.3 F g⁻¹ at 0.5 A g⁻¹. In addition, the relationship between various structures and their properties is systematically investigated.