Enhancing Zn²⁺/H⁺ Joint Charge Storage in MnO₂: Concurrently Tailoring Mn’s Local Electron Density and O’s p-Band Center

Enhancing proton storage in the zinc-ion battery cathode material of MnO₂ holds promise in promoting its electrochemical performance by mitigating the intense Coulombic interaction between divalent zinc ions and the host structure. However, challenges persist in addressing the structural instability caused by Jahn-Teller effects and accurately modulating H⁺ intercalation in MnO₂. Herein, the doping of high-electronegativity Sb with fully occupied d-orbital in MnO₂ is reported. The Sb doping strategy engenders the formation of Mn-O-Sb path in the structure with a strong dipole polarization field, which facilitates the delocalization of e_g orbital electron in Mn and thus mitigates the Jahn-Teller effects. Simultaneously, adjusting the level of Sb doping in MnO₂ leads to modulation of the p-band center of O, optimizing its interaction with hydrogen and thereby enhancing proton storage. Consequently, MnO₂ doped with 6% Sb exhibits commendable performance in both rate capability and cycling endurance, delivering 113 mAh g^-1 at 2 A g^-1 after 2000 cycles. This investigation underscores the crucial role of electronic structural engineering in elevating the electrochemical performance of cathode materials for zinc-ion batteries.