The Emerging of Aqueous Zinc-Based Dual Electrolytic Batteries

As high performance and safety alternatives to the batteries with organic electrolytes, aqueous zinc-based batteries are still far from satisfactory in practical use because of the limitation of the intercalation reaction mechanism and the strict requirements for the cathodes. Very recently, zinc-based dual electrolytic batteries (DEBs), where the cathode and anode are both based on reversible electrolytic reactions, are emerging. It features with electrode-free configuration, thus avoiding the preliminary active materials or electrode fabrication procedures. Meanwhile, the new battery chemistry typically possesses a high specific capacity, output voltage, faster reaction rates, and long cycling life. Herein, the advances of the development of various zinc-based DEBs, including Zn–MnO₂, Zn–Br₂, and Zn–I₂ DEBs, are systematically summarized. This review will focus on the working mechanisms of these batteries and how the decoupling catholyte and anolyte affect their output voltages. The perspectives of the opportunities and challenges are also suggested in the aspects of protecting zinc anode, enhancing volumetric energy density, suppressing fast self-discharge, and developing multifunctional integrated zinc-based DEBs.