Advancements in layered cathode materials for next-generation aqueous zinc-ion batteries: A comprehensive review

Rechargeable aqueous zinc-ion batteries (ZIBs) are considered ideal candidates for next-generation energy storage systems because of their high safety and cost-effectiveness. However, the widespread adoption depends on the discovery of superior cathode materials. Layered electrode materials, equipped with two-dimensional (2D) ion diffusion channels and tunable layered spacing, have aroused substantial research enthusiasm for their potential applications across diverse energy-related technologies. This review comprehensively presents recent research progress in layered cathode materials tailored for aqueous ZIBs, focusing on layered Mn-based, V-based, and Mo-based cathode materials. It examines their structural characteristics and charge storage mechanisms, highlighting their suitability for electrochemical energy storage. Despite their advantages, challenges associated with the layered structure, such as structural instability, low electrical conductivity, and slow ion transport kinetics, are briefly discussed. Therefore, a spectrum of materials engineering techniques from macroscopic to microscopic levels, are highlighted for their pivotal roles in enhancing electrochemical performance. These include morphological tailoring, conductive additive integrating, heterostructure design, interlayer regulation, defects engineering, and heteroatom doping. In the last part, several prospective research avenues are outlined to guild and catalyze further progress in the development of layered cathode materials for aqueous ZIBs.