The practical application of manganese-based cathodes in aqueous zinc-ion batteries is hampered by structural instability and sluggish reaction kinetics. Herein, controlled synthesis of MnO2 polymorphs was achieved by modulating hydrothermal preparation methods. Using (NH4)2C2O4 and NH4F as precursors, we fabricate oxygen-deficient MnO1.88 nanomaterials (denoted 1# and 2#, respectively) featuring distinctive nanowire morphologies. When tested in Zn||MnO2 cells with 2 M ZnSO4 + 0.2 M MnSO4 aqueous electrolyte at room temperature and comparable electrode loadings (∼1.5 mg cm−1), the optimized 2# cathode delivers an initial discharge capacity of 358 mAh g−1 at 1 A g−1 and maintained 85 % capacity retention over 500 cycles at 0.2 A g−1. Structural and electrochemical analysis reveals that the synergistic combination of oxygen vacancies and possible F–Mn interactions in the 2# material synergistically enhances Zn2+ diffusion kinetics and effectively mitigates Jahn-Teller distortion-induced structural degradation. This work establishes a precursor-guided strategy for engineering MnO2 cathodes with simultaneously improved rate capability and cycling stability for aqueous zinc-ion batteries.
For complete article please click link: Mechanistic insights into the impact of MnO2 crystal structures as cathode materials for aqueous zinc-ion batteries – ScienceDirect