Tailoring defect chemistry of 2D transition metal dichalcogenides towards high-performance zinc-based batteries

Zinc–based batteries (ZBBs) have emerged as promising candidates for next-generation energy storage. However, their practical implementation remains hindered by the inherently sluggish electrochemical kinetics and the inferior cycling durability of cathode materials. Layered transition metal dichalcogenides (TMDs) have garnered extensive attention as cathodes for ZBBs, owing to their layered frameworks that facilitate Zn 2+ intercalation/de-intercalation. Nevertheless, pristine TMDs inherently suffer from electrochemically inert basal planes and low electronic conductivity, thus compromising their electrochemical performance. Defect engineering has emerged as an effective strategy to fundamentally enhance the electrochemical activity of TMDs. This review comprehensively outlines the recent advances of defect-engineered TMDs for ZBBs, beginning with an overview of classifications, charge storage mechanisms, and key issues associated with reaction kinetics and interfacial stability of ZBBs. Subsequently, the structural features, synthesis methods, and application potential of TMDs as cathodes across diverse ZBBs are summarized. Particular emphasis is placed on the “defect chemistry–electronic structure–electrochemical performance” paradigm to elucidate structure–property relationships of TMDs. We critically analyze the evolution from single to coupled defects and correlate defect configurations with electrochemical activity and stability. Finally, the remaining challenges and future prospects for the rational design of defect-engineered TMDs for ZBBs toward large-scale applications are discussed.