Reduced Graphene Oxide (rGO)-Based Hybrid Materials as Cathodes in Aqueous Zinc-Ion Batteries: Recent Progress

The growing global energy demand and increasing environmental concerns have created the need for the development of efficient, safe, and sustainable energy storage technologies. While lithium-ion batteries (LIBs) have dominated the energy storage market due to their high energy density and long cycle life, concerns regarding lithium resource scarcity, high cost, and safety risks associated with flammable organic electrolytes have motivated research on alternative batteries. In this context, aqueous zinc-ion batteries (AZIBs) have attracted significant attention as a promising next-generation energy storage system because of their inherent safety, resulting from the utilization of non-flammable aqueous electrolytes, and environmental friendliness, as well as natural abundance and low cost of zinc. Nevertheless, they face various challenges, which hinder their practical applications. Among them, the intrinsic limitations of the cathode materials, including their poor electronic conductivity, sluggish reaction kinetics and structural degradation during charge–discharge cycles, are considered particularly significant. Thus, the scientific community has explored various mitigation strategies, including the combination of cathode materials with carbon-based nanomaterials, such as reduced graphene oxide (rGO), with exceptional physicochemical properties. The present critical review discusses the most recent scientific work published in the literature during the last three years, referring to the combination of rGO with conventional cathode materials, such as manganese-based oxides, vanadium-based oxides, Prussian blue analogues, etc., for the development of next-generation AZIBs with superior electrochemical performance, long-term cycling durability, intrinsic safety, and enhanced sustainability.