Solvent-Free Scalable Preparation of Nickel Manganese Sulfide-Based Hybrids for High-Performance Hybrid Supercapacitors

Abstract

Electrochemical energy storage devices with improved energy and power densities are greatly sought to match the rising demand from electronics to transportation industries. On this front, hybrid supercapacitors are emerging as one of the most promising energy storage technologies in recent years. Hence, to achieve this goal, the rational design and development of highly active, cost-effective and high-performance electrode materials using a facile, efficient, and scalable strategy is an important step. In this work, we demonstrate an environmentally benign, solid-state approach to in-situ producing nanohybrids of transition metal dichalcogenide (TMDs) i.e, nickel-manganese (Ni-Mn) sulfide. Furthermore, its hybridization with carbonaceous materials such as graphene is also targeted. The synthesis encompassed solventless mixing of metal salts (Nickel and manganese), elemental sulfur, and carbon precursors under continuous solid-state dispersion and followed by moderate thermo-annealing. The resulting nanohybrids were thoroughly investigated using several techniques. XRD, HRTEM, SEM, Raman, and BET have been applied to obtain information on the nanohybrid’s morphology, structure, and vibrational and spectroscopic properties. The as-obtained nanostructured hybrid composed of Ni-Mn sulfide and graphene) was used as a positive electrode material (cathode) in hybrid supercapacitors. The electrochemical studies (CV, GCD, EIS) of the as obtained the devices were assessed to evaluate the charge storage performance, charge storage capability, and stabilities. The electrochemical performance of hierarchically structured Ni-Mn-S-based hybrid electrodes using our solvent-less preparation approach paves a new pathway for developing novel metal chalcogenides for high-performance hybrid supercapacitors.