Aqueous Zinc-Iodine Batteries: From Electrochemistry to Energy Storage Mechanism

As one of the most appealing energy storage technologies, aqueous zinc-iodine batteries still suffer severe problems such as low energy density, slow iodine conversion kinetics, and polyiodide shuttle. This review summarizes the recent development of ZnI2 batteries with a focus on the electrochemistry of iodine conversion and the underlying working mechanism. Starting from the fundamentals of ZnI2 batteries, the electrochemistry of iodine conversion and zinc anode, as well as the scientific problems existing in ZnI2 batteries are introduced. The concrete strategies dealing with cathode, anode, electrolyte, and separator challenges confronting ZnI2 batteries are elaborated as well. To deepen the understanding of the electrochemistry of ZnI2 batteries, the recent important findings of the underlying working mechanism of different ZnI2 batteries are summarized in detail. Finally, some guidelines and directions for ZnI2 batteries are also provided. This review is expected to deepen the understanding of ZnI2 battery electrochemistry and promote their practical applications in the future. This work summarizes the recent progress on ZnI2 batteries with a focus on iodine conversion electrochemistry and the working mechanism. The fundamentals, the challenges faced by ZnI2 batteries, and the latest achievements in cathodes, anodes, electrolytes, and separators, as well as the energy storage mechanisms are elaborately discussed.image