Binary and Ternary Solvents Influenced Growth of Thiol Staples Modified Nickel Nanoclusters and Their Tunable Supercapacitance

Nickel (Ni), a hard silver-white transition metal, is widely recognized for its catalytic and electrochemical properties.In this study, thiol-protected NiO@Ni(II)SR nanoclusters were synthesized via a solvent recrystallization approach using binary (methanol-water, acetonewater) and ternary (methanol-water-acetone) solvent systems to precisely regulate particle nucleation and growth.Density Functional Theory (DFT) frontier orbital analysis revealed strong electron delocalization across Ni, S, and O atoms, confirming efficient ligand-to-metal charge transfer with HOMO and LUMO energies of 0.23306 a.u. and 0.18493 a.u., respectively.The results highlight the critical roles of metal-ligand interactions, reducing agents, and solvent polarity in controlling nanocluster size, surface stabilization, and electronic structure.The synthesized nanoclusters exhibited solvent-dependent particle sizes of 1-9 nm (methanolwater), 1-5 nm (acetone-water), and 1-20 nm (methanol-water-acetone).Electrochemical analysis demonstrated high specific capacitances of ~745 F/g, ~804 F/g, and ~778 F/g, respectively, across the solvent systems.Notably, a ternary phase diagram was established for the first time, illustrating the influence of solvent polarity and microstructural variations on NiO@Ni(II)SR nanocluster growth and their enhanced performance in supercapacitor applications.