Intercalation-Coupled Zn ²⁺ Transfer Enables Reversible ZnS Conversion in Aqueous Zn–S Batteries

Aqueous Zn–S batteries offer high safety and low cost, but sluggish ZnS reoxidation and cathode passivation limit capacity and efficiency. Herein, we report an intercalation-coupled redox catalysis strategy using manganese hexacyanoferrate (MnHCF) confined in polypyrrole (PPy) nanoreactors to mediate ZnS reoxidation. The reversible iron redox center in MnHCF couples with prezincation/deintercalation, creating a chemical potential gradient that drives Zn2+ from ZnS to MnHCF. This mechanism removes Zn2+ from the reaction front, enhancing Zn2+ mobility, reducing charge-transfer resistance, lowering the reactivation barrier, preventing passivation, and ensuring uniform conversion to S8. The cathode delivers 1245 mAh g–1 at 0.4 A g–1 and 928 mAh g–1 at 1 A g–1 with an initial Coulombic efficiency of 99.983%, retaining 734 mAh g–1 and 99.941% after 400 cycles. Practical pouch cells deliver 86 Wh kg–1, and wearable microbatteries reach 563 μWh cm–2. This work offers an effective catalytic strategy for high-energy, long-life Zn–S batteries.