Enhancing Zn-MnO2 Battery Performance with Hydrogen-Bonded MnO2 Interfaces in Wet Nonaqueous Electrolytes

Abstract

The quest for sustainable and high-performing battery technologies has directed attention towards Zinc (Zn)-manganese dioxide (MnO2) based rechargeable batteries. These batteries emerge as a viable alternative to lithium-ion systems, particularly due to their advantageous raw material supply, cost, and performance parameters. Despite their potential, Zn-MnO2 batteries face operational challenges, including gas evolution, Zn self-corrosion, and dissolution of the host material when utilized in mild acid aqueous electrolytes. Addressing these issues, our research explores the efficacy of wet nonaqueous electrolytes as a solution. Previously, we demonstrated a substantial enhancement in battery performance (~200 mAh/g of MnO2) by incorporating a specific proportion of water into the nonaqueous electrolyte. Building on this foundation, our current study investigates the role of hydrogen-bonded pillars, particularly proton and ammonium cations, in augmenting the interfacial properties of MnO2. This modification aims to bolster surface kinetics, thereby elevating battery performance closer to that of aqueous systems. Employing a suite of material characterization techniques, including in-situ X-ray absorption spectroscopy (XAS), Raman spectroscopy, and synchrotron X-ray diffraction (XRD), we observed a notable performance improvement (~270 mAh/g), while maintaining stability. These findings hold significant promise for advancing the practical application of MnO2-based hosts in Zn-MnO2 batteries, marking a stride towards next-generation energy storage solutions.