Enhancement of Zn/Zn²⁺ Reversibility Using Molecular Materials in Aqueous Zinc-Ion Batteries: A Review

Development of aqueous zinc ion batteries (AZIBs) is of recent interest for sustainable and scalable energy storage. This review focuses on the development of all components of AZIBs, namely, electrolytes, anodes, cathodes, and a separator, using molecular materials to enhance battery performance. It systematically categorizes different kinds of molecular materials based on their diverse functionalities, intrinsic properties, and applicability in different components of batteries. Each component has different functions and thus has different requirements from the molecular materials. By comparing the impact of each factor on cycle life, coulombic efficiency, capacity, and energy density, this comprehensive literature survey provides a critical insight into how to enhance the battery performance metrics for practical applications. We emphasize diagnosing the failure mechanism of the battery by close investigation of the health of each component, including cathode dissolution, anode corrosion, dendrite formation, SEI structure determination, hydrogen evolution, and solvation structure. Hence, this review offers a very deep understanding of potential future research advancement in view of current research trends. It introduces a new concept of utilizing hybrid materials in tuning the electrodes, electrolytes, and separator. This review will provide invaluable insights and pragmatic strategies for the advancement of aqueous zinc-ion batteries using molecular materials.