摘要：SummaryRechargeable aqueous Zn/manganese dioxide (Zn/MnO2) batteries are attractive energy storage technology owing to their merits of low cost, high safety, and environmental friendliness. However, theβ-MnO2cathode is still plagued by the sluggish ion insertion kinetics due to the relatively narrow tunneled pathway. Furthermore, the energy storage mechanism is under debate as well. Here,β-MnO2cathode with enhanced ion insertion kinetics is introduced by the efficient oxygen defect engineering strategy. Density functional theory computations show that theβ-MnO2host structure is more likely for H+insertion rather than Zn2+, and the introduction of oxygen defects will facilitate the insertion of H+intoβ-MnO2. This theoretical conjecture is confirmed by the capacity of 302 mA h g−1and capacity retention of 94% after 300 cycles in the assembled aqueous Zn/β-MnO2cell. These results highlight the potentials of defect engineering as a strategy of improving the electrochemical performance ofβ-MnO2in aqueous rechargeable batteries.Graphical AbstractDisplay OmittedHighlights•A conversion reaction mechanism is observed for Zn/β-MnO2system•The binding energy of H+insertion is reduced by introducing oxygen defects•The introduction of oxygen defects increases ion insertion channels•Zn/D-β-MnO2battery delivers good performance even at high mass loadingEnergy Storage; Nanomaterials; Energy Materials
