A synergistic triple-effect modification strategy for advanced manganese-based zinc-ion batteries and hybrid supercapacitors

Manganese dioxide (MnO 2 ) has gained extensive attention as a potential cathode candidate for aqueous zinc-ion batteries (AZIBs) and hybrid supercapacitors (HSCs). Nevertheless, its practical deployment remains limited due to slow electrochemical kinetics and poor structural robustness upon cycling. Herein, a tri-functional modification strategy is proposed to construct high-performance MnO 2 cathodes (Na 2 S 2 O 3 -MnO 2 ) by introducing sodium thiosulfate (Na 2 S 2 O 3 ) as a chelating agent, Na + dopant, and reducing agent. Through this approach, Na + -intercalated MnO 2 nanosheet architectures are constructed, featuring refined particle dimensions, expanded specific surface area, and abundant oxygen vacancies. The cooperative contribution from interlayer Na + stabilization and vacancy modulation markedly accelerates ion-transport behavior while reinforcing structural integrity. The Na 2 S 2 O 3 -regulated MnO 2 cathode exhibits a reversible capacity of 343 mAh g −1 at 0.3 A g −1 and maintains 71.6% of its initial capacity after 2000 cycles at 1 A g −1 . In addition, a HSC using this material as the positive electrode and activated carbon as the counter electrode demonstrates outstanding cycling durability over 5000 cycles at 2 A g −1 . The AZIB mechanism involves H + /Zn 2+ intercalation/deintercalation, Zn 4 SO 4 (OH) 6 ·nH 2 O and MnO 2 dissolution/deposition, and prolonged-cycle phase evolution, whereas H + intercalation/deintercalation dominates in HSCs. Overall, this study offers a scalable strategy for MnO 2 -based cathodes, accelerating the development of AZIBs and HSCs.