A universal H2O2-induced phase transformation of nickel sulfide towards sulfur-rich component

It is widely accepted that the property of material is closely related to their morphology, phase, and composition. Nickel sulfides (NSs) possess various phases and morphologies, which enriches their electrochemical performance, but the difficulty in controlled synthesis of NSs poses a huge challenge for optimizing their property. Especially, it is extremely challenging to effectively control the phase and composition without changing the morphology. Herein, we for the first time demonstrate a facile one-step H 2 O 2 -induced method to controllably tune the phase and composition of NSs. We found that changing the amount of H 2 O 2 in precursor can achieve the phase transformation from sulfur-deficient to sulfur-rich component, while the shape of obtained products would not be greatly changed. It is worth noting that this result would benefit us to study the phase-related properties independently. Also, the H 2 O 2 -induced tactic shows high “adaptability” for different sulfur sources, such as the conventional L-cysteine, glutathione, thiourea, and thioacetamide. When tested in KOH electrolyte, we found that the performance of NSs have no obvious relation with their phase and composition, but mainly correlate with morphology. Among which, the optimum TU-400 with polyhedron-like shows a highest specific capacity of 197.8 mAh g −1 at 1 A g −1 .