Abstract

Nonaqueous zinc-ion batteries (NZIBs), featuring manganese dioxide (MnO₂) cathodes, positions them as viable options for large-scale energy storage systems. Herein, we demonstrate the use of ammonium cation as a pre-intercalant to improve the performance of δ-MnO 2 cathode in wet dimethyl sulfoxide-based electrolytes. Employing in-situ X-ray absorption spectroscopy, Raman spectroscopy, and synchrotron Xray diffraction, we reveal that the integration of ammonium cations promotes the formation of NH--O-Mn networks. These networks are crucial for manipulating distortion of the MnO₆ octahedral units during discharging, thereby mitigating charge disproportionation, which is a primary limitation to MnO₂'s chargestorage efficiency. The modified MnO 2 , through this idea, displays a notable improvement in capacity (~247 mAh/g) and can pass charge-discharge cycles up to 500 cycles with a capacity retention of 85%.

These findings underscore the potential of modified MnO₂ in advancing MnO₂-based hosts for Zn-MnO₂ batteries, marking significant progress towards next-generation energy storage solutions.