• Hierarchical Zn2+/NH4+ solvation structure induces cathodic interfacial Helmholtz plane reconfiguration to enhance spatial charge density and capacity storage.
• Hydrated NH4+ ions afford high-kinetics and ultrastable C‧‧‧H charge storage due to a much lower desolvation energy barrier compared with large-sized Zn(H2O)6 2+ (5.81 vs. 14.90 eV).
• Interfacial Zn2+/NH4+ co-storage endow the hybrid capacitor with high capacity (240 mAh g−1), large-current tolerance (50 A g−1) and ultralong lifespan (400,000 cycles).
• The NH4+-modulated strategy provides new insights into cathode–electrolyte interface design for advanced zinc-based energy storage.