Dialectical Observation of Controllable Electrodeposited Ni Nanocones: the Unification of Local Disorder and Overall Order

Dense and ordered Ni nanocones with regular spiral textures had been successfully synthesized via a simple and inexpensive electrodeposition process in the solution containing sodium chloride (NaCl), nickel chloride hexahydrate (NiCl₂·6H₂O), and boric acid (H₃BO₃). After analyzing the microstructure, a more optimized possible growth mechanism of Ni nanocones was proposed, in which the growth process was divided into local and global aspects, named multi-dimensional growth mechanism of global order and local disorder. In an area small enough, any subtle state changes would cause disorder of Ni atom arrangement, which made the local microstructure appear disordered, but from a macro perspective, the difference between two adjacent disorders caused by different statuses was too small to be well reflected, only when the difference in state was large enough can the change be observed in the macroscopic appearance, so the global was orderly. Meanwhile, we found that the microstructure of Ni nanocones would be controlled in the electrodeposition solution by adjusting the experiment parameters such as the concentration of NaCl, NiCl₂·6H₂O, and H₃BO₃, which indirectly determined the microstructure in a large extent via controlling the generation of intermediate products and the pH.