Aqueous Zinc-Sulfur Batteries: From Challenges to Strategies

Aqueous Zn-S batteries (AZSBs), including conventional and decoupled AZSBs, are suitable options for advanced electrochemical energy storage systems. They are cost-effective with safety, high theoretical capacity, and power density. Nevertheless, many inherent hurdles need to be overcome to make AZSBs practically feasible, including irreversible transformation of the sulfur cathode, instability of the Zn anode, and incompatibility of the electrolyte. This review presents a comprehensive evaluation of AZSBs, emphasizing the configurations and electrode reactions, challenges, strategies, and prospects for the future. First, the electrochemistry behavior of AZSBs is reviewed, encompassing both conventional and decoupled battery configurations, along with their respective electrode reactions. Second, various sources, hosts, and additives for sulfur are identified that can effectively enhance the reversibility of the sulfur cathode. Third, approaches to constructing the solid electrolyte interphase on the Zn anode and facilitating Zn alloying are discussed as key strategies for anode protection. Fourth, the selection of zinc salts and the employment of organic co-solvents are explored to regulate electrolytes. Finally, the thoughts on future research development in AZSBs are presented to build better aqueous batteries.