ABSTRACT Manganese‐based cathode materials hold great promise for aqueous zinc‐ion batteries (AZIBs) due to their high operating voltage and low cost. Among these, manganese dioxide (MnO 2 ) cathodes exhibit particularly promising electrochemical characteristics but face critical challenges including insufficient electrical conductivity and rapid capacity fading. To address these issues, manganese oxyhydroxide (MnOOH) and α ‐MnO 2 have been studied. MnOOH offers excellent cycling stability but suffers from a relatively low specific capacity, whereas α ‐MnO 2 delivers high specific capacity but exhibits poor cycling stability. A rationally designed MnOOH/ α ‐MnO 2 composite was synthesized via a crystal phase transformation method, using δ ‐MnO 2 as the precursor. The composite features a unique nanowire and nanorod morphology and is employed as a cathode material for AZIBs. It outperforms its individual components, achieving a high specific capacity of 233.4 mAh g − 1 after 750 cycles at 1 A g −1 . At an elevated current density of 2 A g −1 , it maintains a stable specific capacity of 85.0 mAh g −1 after 17,000 cycles. Comprehensive mechanistic investigations reveal that the zinc storage process involves the co‐intercalation/extraction of Zn 2+ and H + ions, coupled with reversible MnO 2 dissolution and redeposition. These findings highlight the potential of MnOOH/ α ‐MnO 2 composites as high‐performance cathode materials for AZIBs, effectively addressing the challenges of capacity limitation and cycling stability.
Chen et al. (Fri,) studied this question.