Aqueous Rechargeable Zn-ion Batteries: Strategies for Improving the Energy Storage Performance

The growing demand for the renewable energy storage technologies stimulated the quest for efficient energy storage devices. In recent years, the rechargeable aqueous zinc-based battery technologies are emerging as a compelling alternative to the lithium-based batteries owing to safety, eco-friendliness, and cost-effectiveness. Among the zinc-based energy devices, rechargeable zinc-ion batteries (ZIBs) are drawing considerable attention. However, they are plagued with several issues, including cathode dissolution, dendrite formation, etc.. Despite several efforts in the recent past, ZIBs are still in their infant stages and have yet to reach the stage of large-scale production. Finding stable Zn²⁺ intercalation cathode material with high operating voltage and long cycling stability as well as dendrite-free Zn anode is the main challenge in the development of efficient zinc-ion storage devices. This Review discusses the various strategies, in terms of the engineering of cathode, anode and electrolyte, adopted for improving the charge storage performance of ZIBs and highlights the recent ZIB technological innovations. A brief account on the history of zinc-based devices and various cathode materials tested for ZIB fabrication in the last five years are also included. The main focus of this Review is to provide a detailed account on the rational engineering of the electrodes, electrolytes, and separators for improving the charge storage performance with a future perspective to achieving high energy density and long cycling stability and large-scale production for practical application.