Aqueous Rechargeable Zinc–Metal Batteries: A Critical Analysis

The recent re-emergence of aqueous Zn–metal battery technologies, including Zn-ion and electrolytic stripping–plating chemistry, represents potentially viable batteries, particularly in terms of their manufacture–installation costs. However, many critical factors need to be addressed to ensure further advancements in these emerging Zn–metal technologies along with improving the existing Zn-based technologies, including alkaline Zn–MnO2, Zn–Ni, and Zn–air batteries. Specifically, alkaline Zn–MnO2 batteries face the challenge of complete consumption of the 2e– with respect to MnO2, while Zn–Ni batteries struggle in terms of the anode stability and the cost of cathodes. As such, research has yet to resolve the mildly acidic Zn–MnO2 battery's intricate diverse electrochemical mechanism(s), while the strong acidic–alkaline decoupled Zn–MnO2 battery suffers from anode–cathode dissolutions. This Perspective provides the status of aqueous Zn–metal battery technologies and the factors associated with their practical developments along with our simulation of energy density calculations.