Advanced aqueous batteries: Status and challenges

Abstract The electricity grids with high stability and reliability require a desired balance of energy supply and demand. As the typical sustainable energy, the intermittent solar and wind would result in electricity grid instability. Aqueous batteries have been considered to be appealing stationary power sources for sustainable energy. Advanced aqueous batteries can address the safety concern derived from the employment of highly toxic and flammable organic solvents in lithium-ion batteries together with the poor cycle life presented in commercialized aqueous rechargeable batteries. This review will introduce several kinds of newly developed aqueous batteries, including aqueous Li (Na)-ion batteries, zinc anode-based batteries (Zn-metal oxide, Zn-air, Zn–Br_2, and Zn–Ni(OH)_2 batteries), and Ni(OH)_2 cathode-based batteries (Ni(OH)_2–MH and Ni(OH)_2-organic composite batteries). The materials, mechanisms, and battery techniques for the above aqueous batteries will be introduced in detail. The status and challenges for the application of aqueous batteries will also be discussed. Graphical abstract Highlights The status for advanced aqueous batteries are summarized in detail. The challenges for the application of aqueous batteries are discussed. Discussion The aqueous batteries are considered as the promising large-scale energy storage systems. However, the narrow voltage window of aqueous electrolyte limits the electrochemical performance of aqueous batteries. Moreover, the instabilities of electrode materials in aqueous electrolyte further hamper the practical application of aqueous batteries. Consequently, large efforts involving scientific and technical communities are required to be devoted with the aim to facilitate the development of aqueous batteries.