DNA‐Assisted Synthesis of Defect‐Rich MnO ₂ Cathodes for High‐Rate and Long‐Life Aqueous Zinc‐Ion Batteries

ABSTRACT Designing MnO 2 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 δ‐MnO 2 nanoflakes with slightly expanded interlayer spacing, enriched Mn 3 + sites and oxygen‐related defects which enable rapid Zn 2+ insertion/extraction without structural collapse. Comprehensive FTIR, XPS, XRD, and N 2 sorption analyses confirm increased Mn 3 + 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‐MnO 2 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%.