Phytic Acid Anions‐Mediated Surface Charge Modulation of Manganese Oxide for High‐Rate and Stable Zn//MnO 2 Batteries

ABSTRACT MnO 2 has been considered as a promising cathode for aqueous zinc‐ion batteries (AZIBs) due to its environmental benignity, low cost, and high theoretical capacity. However, the severe Mn 2+ dissolution and sluggish interfacial reaction kinetics of MnO 2 dramatically impede its practical applications. Herein, the phytic acid anion‐functionalized MnO 2 (PCA‐MO) cathode with electron‐rich surface is reported for high‐performance AZIBs. Specifically, phytic acid anion with lone pairs of electrons can increase surface charge density and form stronger interactions with Zn 2+ , achieving interfacial Zn 2+ enrichment and promoting charge transfer. Moreover, the phytic acid anion layer acts as a protective barrier, preventing direct contact between the electrode and the electrolyte, thereby effectively suppressing Mn 2+ dissolution. Therefore, the PCA‐MO delivers high specific capacity (332 mAh g −1 at 0.2 A g −1 ), superior rate performance (111 mAh g −1 at 5.0 A g −1 ), and long‐term cycling stability for 1000 cycles at 2.0 A g −1 . This work provides new insights into developing high‐performance Mn‐based cathodes for aqueous batteries.