Emerging bismuth-based materials for zinc-based electrochemical energy storage: fundamentals, advances, and perspectives

Bismuth-based materials have emerged as multifunctional components for zinc-based electrochemical energy storage systems, owing to their unique electronic structures, diverse crystal chemistry, high hydrogen-evolution overpotential, and favourable zinc affinity. In this review, we systematically summarize the recent progress in the design and application of bismuth-based materials for zinc-based electrochemical energy storage, including aqueous zinc-ion batteries (AZIBs), zinc-air batteries (ZABs), zinc-based flow batteries (ZFBs), and zinc-ion hybrid capacitors (ZIHCs). Specifically, we focus on various categories of bismuth-based materials‒metallic bismuth, bismuth oxides, chalcogenides, halides, oxyhalides, alloys, and heterostructures‒within the context of their crystal structures and corresponding electrochemical functionalities. A range of key factors are critically analysed, including synthesis methods, structural regulation, defect engineering, and reaction mechanisms, complemented by advanced in situ/operando characterization and density functional theory (DFT) calculations. The multifunctional roles of these materials are then featured across different device components‒anodes, cathodes, electrolytes, and interfaces‒covering their functions in zinc deposition regulation, charge storage, oxygen electrocatalysis, and side-reaction suppression. We conclude the review with a perspective highlighting the remaining challenges and future research directions, emphasizing the need for integrated multiscale design, scalable manufacturing, electrolyte co-optimization, and data-driven discovery to translate the intrinsic advantages of bismuth chemistry into practical high-performance zinc-based energy storage technologies.