ScholarWorks@성균관대학교

초록

Designing MnO2 cathodes capable of operating at high rates without structural degradation remains a major challenge for aqueous zinc-ion batteries. In this work, we introduce a simple DNA-assisted hydrothermal synthesis strategy in which deoxyribonucleic acid (DNA) acts as a molecular precursor that generates phosphate- and nitrogen-containing groups coordinate with Mn ions during nucleation. This coordination yields defect-rich, loosely stacked delta-MnO2 nanoflakes with slightly expanded interlayer spacing, enriched Mn3 + sites and oxygen-related defects which enable rapid Zn2+ insertion/extraction without structural collapse. Comprehensive FTIR, XPS, XRD, and N2 sorption analyses confirm increased Mn3 + content, defect-rich local environments, and enhanced surface area and mesoporosity, which collectively facilitate fast charge storage kinetics and accessible redox centers. Benefiting from these synergistic features, the DNA-MnO2 cathode delivers a high capacity of 293.3 mAh g-1 at 0.2 A g-1 and maintains 121.6 mAh g-1 at 10 A g-1. It also exhibits excellent cycling stability, retaining 86.5% capacity after 500 cycles at 2 A g-1 and delivering 53.8 mAh g-1 after 10 000 cycles at 10 A g-1 with Coulombic efficiency above 99.8%.

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