Electrolyte formulas of aqueous zinc ion battery: A physical difference with chemical consequences

Researchers have recently redirected their attention toward aqueous batteries in pursuit of safety and affordability. The water-based electrolyte promises many appealing merits such as non-flammability and environmental friendliness but is also cursed with low energy density. In an attempt of lifting the curse, many efforts have been made to re-formulate the aqueous electrolyte, which seems unlikely to succeed without understanding the interplay between electrolytes’ physical properties and electrochemical performance. Starting from the composition of electrolytes, we discuss how various formulas of zinc ion battery electrolytes lead to diverse electrochemical performances. By evaluating the electrochemical performance of batteries in five metrics, it provides a la carte electrolyte designing strategies with different battery purposes.