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

The quest for sustainable and high-performing battery technologies has directed attention towards Zinc (Zn)-manganese dioxide (MnO 2 ) 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-MnO 2 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 MnO 2 ) 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 MnO 2 . 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 MnO 2 -based hosts in Zn-MnO 2 batteries, marking a stride towards next-generation energy storage solutions.