Rechargeable aqueous zinc-manganese dioxide batteries with high energy and power densities

TLDR

Alkaline zinc‑manganese dioxide batteries dominate primary battery use, but making them rechargeable remains challenging. The authors aim to demonstrate a high‑performance rechargeable Zn‑MnO₂ battery using an aqueous mild‑acidic zinc triflate electrolyte that enables Zn²⁺ intercalation into the MnO₂ cathode. The battery operates by converting tunnel‑structured MnO₂ to layered zinc‑buserite during first discharge, permitting Zn²⁺ intercalation, and the electrolyte promotes a protective porous manganese oxide layer. The Zn‑MnO₂ battery delivers 225 mAh g⁻¹ reversible capacity, 94 % retention after 2000 cycles, and a pouch cell energy density of 75.2 Wh kg⁻¹, indicating high performance and suitability for large‑scale storage.

Abstract

Although alkaline zinc-manganese dioxide batteries have dominated the primary battery applications, it is challenging to make them rechargeable. Here we report a high-performance rechargeable zinc-manganese dioxide system with an aqueous mild-acidic zinc triflate electrolyte. We demonstrate that the tunnel structured manganese dioxide polymorphs undergo a phase transition to layered zinc-buserite on first discharging, thus allowing subsequent intercalation of zinc cations in the latter structure. Based on this electrode mechanism, we formulate an aqueous zinc/manganese triflate electrolyte that enables the formation of a protective porous manganese oxide layer. The cathode exhibits a high reversible capacity of 225 mAh g-1 and long-term cyclability with 94% capacity retention over 2000 cycles. Remarkably, the pouch zinc-manganese dioxide battery delivers a total energy density of 75.2 Wh kg-1. As a result of the superior battery performance, the high safety of aqueous electrolyte, the facile cell assembly and the cost benefit of the source materials, this zinc-manganese dioxide system is believed to be promising for large-scale energy storage applications.The development of rechargeable aqueous zinc batteries are challenging but promising for energy storage applications. With a mild-acidic triflate electrolyte, here the authors show a high-performance Zn-MnO2 battery in which the MnO2 cathode undergoes Zn2+ (de)intercalation.