Recent progress in Core@Shell sulfide electrode materials for advanced supercapacitor devices

Abstract

Highly conductive and surface area complex hierarchical 3D core@shell nanostructures made of multi-metallic multi-valence sulfides are being specially designed as electrode materials of high performance and high power supercapacitors. In fact, bimetallic and trimetallic sulfides have outstanding redox properties as compared with the corresponding single-phase sulfide based materials, and much higher electrical conductivity than the analogue oxide materials, being excellent materials for the design of core@shell structures with exceptional charge capacity, power, and energy performance. For this purpose, the core material should exhibit high charge diffusion rates and large specific capacitance, while the shell should improve the surface area by promoting a greater accessibility to the electroactive sites thus maximizing the charge capacity and conductivity. In this context, a rational design of nanostructured materials encompassing advanced 2D materials (such as graphene, MXene, black phosphorus, transition metal hydroxides, etc.), as well as carbon materials such as CNTs and carbon cloth, seems to be a very promising strategy to realize flexible enough electrode materials for the development of wearable devices, self-charged energy storage devices and microsupercapacitors. In all cases, multi-metallic sulfide-based core@shell materials play a key role as electroactive materials for realization of high performance, portable and flexible energy storage devices paving the way to a more advanced and sustainable society.