Electron‐Driven‐Proton Intercalation in δ‐MnO ₂ to Unlock Fast‐Charging Aqueous Zinc‐Ion Batteries

In aqueous zinc‐ion batteries (AZIBs), the H + intercalation endows the battery with high reversible capacity and outstanding rate performance due to its superior electrochemical kinetics. However, how to boost the proton intercalation remains a challenge. Herein, a bottom‐up concept with electron‐driven‐proton intercalation strategy was proposed through Ca 2+ pre‐intercalation and S 2− doping into δ‐MnO 2 (Ca‐MnO 2 ‐S). The co‐doping effect synergistically increases the electron concentration in δ‐MnO 2 , improving the H + insertion capacity and thus the electrode reaction dynamics. Meanwhile, the inserted H + ion acts as a “lubricant” to further facilitate the Zn 2+ transport. Consequently, the Ca‐MnO 2 ‐S cathode exhibits excellent H + /Zn 2+ storage performance with a high capacity (400.4 mAh g −1 at 0.1 A g −1 ), superior rate capability (136.3 mAh g −1 at 20 A g −1 ) and excellent long‐term cycling stability (88.1% capacity retention after 5000 cycles at 5 A g −1 ) in AZIBs. Moreover, pouch cells further validate its fast‐charging capability and high service durability across a wide temperature range from −10°C to 40°C. This work introduces an electron‐concentration‐modulation strategy to regulate the proton intercalation, providing both mechanistic insight and practical guidance for advanced Zn‐storage cathode design.