Engineering p‐Band Center of Oxygen Boosting H⁺ Intercalation in δ‐MnO₂ for Aqueous Zinc Ion Batteries

Abstract

In aqueous zinc ion batteries (ZIBs), the H⁺ intercalation possesses superior electrochemical kinetics with excellent rate capability, however, precisely modulating H⁺ intercalation has been still challenging. Herein, a critical modification of pre-intercalating metal ions in the MnO₂ interlayer (M-MnO₂ ) with controllable p-band center (ϵ_p ) of O is reported to modulate the H⁺ intercalation. The modulation of metal-O bond type and covalency degree on the average charge of O atom results in optimized ϵ_p and H⁺ adsorption energy for M-MnO₂ , thus promoting the balance between H⁺ adsorption and desorption, which plays a determinant role on H⁺ intercalation. The optimized Cu-MnO₂ delivers superior rate capability with the capacity of 153 mAh g^-1 at a high rate of 3 A g^-1 after 1000 cycles. This work demonstrates that ϵ_p could be a significant descriptor for H⁺ intercalation, and tuning ϵ_p effectively increases H⁺ intercalation contribution with excellent rate capability in ZIBs.