A key advance toward practical aqueous Zn/MnO2 batteries via better electrolyte design

Abstract

Rechargeable aqueous devices, such as alkaline Zn/MnO₂ batteries, hold strong potential for large-scale energy storage. However, they face limitations related to zinc and electrolyte degradation. Here, in the spirit of practicality, we have addressed these limitations by developing strategies aiming at resolving issues with the electrolyte, anode, and cathode independently at first, and then in synergy. We propose innovative electrolyte designs that incorporate select organic molecules to leverage hydrogen bonding interactions, reducing Zn nuclei reactivity via the formation of a stable solid electrolyte interphase (SEI). Our optimized Zn/MnO₂ batteries demonstrate high stability, achieving a gravimetric capacity of ∼450 mAh/g (MnO₂) and 90% capacity retention. Furthermore, we systematically show the scalability of our methods, moving from a Swagelok cell prototype (3–6 mg/cm² of mass loading) to cylindrical-type cell (30 mg/cm²). These batteries can operate at unprecedentedly high temperatures of up to 55°C, while offering an energy density of 150 Wh/kg.