The Chalkboard: Aqueous Batteries 2.0: A Noble Pursuit or a Fool’s Errand?

Lithium-ion batteries are a shining example of our community’s contribution to the world. While the pre-lithium-ion world was dominated by aqueous batteries such as lead-acid, alkaline zinc, and nickel–metal hydride (i.e., Aqueous Batteries 1.0), the switch to nonaqueous electrolytes was critical to expanding the voltage stability window, and in turn, enabling high energy density lithium-ion batteries. Such a leap in energy density was instrumental to new technologies like passenger electric vehicles, smartphones, and powerful laptops. The prominence of lithium-ion research and development over the past decades has (somewhat rightly) lured us away from aqueous batteries. However, in recent years, interest in aqueous batteries has renewed—as a viable technology for storing energy on the grid for long durations—and multiple chemistries such as iron-air and quinone-based flow batteries are being explored (Aqueous Batteries 2.0). At this juncture, an important question for our community is whether we should dedicate sizeable efforts to enabling a new generation of aqueous batteries as opposed to our ongoing pursuit of energy-dense beyond–lithium-ion batteries for hard-to-electrify transportation modes such as aviation.