The role of graphene and molybdenum disulfide in rechargeable energy storage systems: Perspective and challenges

To offset the intermittent nature, renewable energy sources must be paired with energy storage systems (ESS) to cater to the demand for clean energy solutions. The performance characteristics requirements of these ESS are application-specific, say batteries are characterized by their high energy capacity while supercapacitors offer greater power density. Currently, the research concentration in this domain is on improving the performance parameters of proven energy storage chemistries. Two-dimensional (2D) materials characterized by high specific surface area, and tunable physical and electrical properties are explored extensively to enhance ESS performance. This review comprehends the progress made by two typical 2D materials, Graphene and Molybdenum disulfide, to enhance the energy/ power capacity, and life span of a few chosen rechargeable storage chemistries, lithium-ion, lithium-sulfur batteries, supercapacitors, and flow batteries. Further the review presents the current state of ESS, the challenges identified so far which restrict their capacity and life span, and the solutions employed to date. Finally, the challenges associated with these solutions are critically analyzed to suggest future directions and research perspectives in this domain.