Abstract
Compared with Zn(2+), the current mainly reported charge carrier for zinc hybrid capacitors, small-hydrated-sized and light-weight NH(4)(+) is expected as a better one to mediate cathodic interfacial electrochemical behaviors, yet has not been unraveled. Here we propose an NH(4)(+)-modulated cationic solvation strategy to optimize cathodic spatial charge distribution and achieve dynamic Zn(2+)/NH(4)(+) co-storage for boosting Zinc hybrid capacitors. Owing to the hierarchical cationic solvated structure in hybrid Zn(CF(3)SO(3))(2)-NH(4)CF(3)SO(3) electrolyte, high-reactive Zn(2+) and small-hydrate-sized NH(4)(H(2)O)(4)(+) induce cathodic interfacial Helmholtz plane reconfiguration, thus effectively enhancing the spatial charge density to activate 20% capacity enhancement. Furthermore, cathodic interfacial adsorbed hydrated NH(4)(+) ions afford high-kinetics and ultrastable C‧‧‧H (NH(4)(+)) charge storage process due to a much lower desolvation energy barrier compared with heavy and rigid Zn(H(2)O)(6)(2+) (5.81 vs. 14.90 eV). Consequently, physical uptake and multielectron redox of Zn(2+)/NH(4)(+) in carbon cathode enable the zinc capacitor to deliver high capacity (240 mAh g(-1) at 0.5 A g(-1)), large-current tolerance (130 mAh g(-1) at 50 A g(-1)) and ultralong lifespan (400,000 cycles). This study gives new insights into the design of cathode-electrolyte interfaces toward advanced zinc-based energy storage.