Simple and affordable synthesis of a binder-free nickel-zinc sulfide electrode for high-performance supercapacitors

Abstract

Due to the increasing demand for renewable energy solutions, aqueous energy systems have emerged as promising and sustainable technologies. Nanostructured transition metal sulfides, renowned for their exceptional properties, are prime candidates for electrochemical supercapacitors. In this study, we present the synthesis of nickel-zinc sulfide (Ni-Zn-S) as a binder-free supercapacitor material using the affordable successive ionic layer adsorption and reaction simple technique. The active nanomaterial was directly deposited onto a 3D Ni foam current collector substrate, negating the need for a binder. The synergistic combination of Ni and Zn enhances the electrode capacitance. Various electrochemical techniques were used to evaluate the loaded active material as a binder-free supercapacitor electrode in a 6 M KOH electrolyte. Results indicate pseudocapacitive performance, achieving a high specific capacitance of 400F/g at 0.7 A/g. This material retains 97 % of its capacity, even after 2000 cycles, showcasing exceptional long-term cycling stability. These findings underscore the potential of the Ni-Zn-S electrode for delivering low-cost, high-performance supercapacitors.