Modification of Organic–Inorganic Bilayer Interface on Zinc Foil Surface for Ultra-Long Stability Zinc-Ion Supercapacitors

Rechargeable aqueous zinc-ion hybrid capacitors are considered to have promising application prospects owing to their low cost, superior environmental friendliness, and safety. However, during the operation of zinc anodes, dendrite growth, hydrogen evolution, and corrosion reactions tend to occur, which can destabilize the anode interface and consequently degrade the overall performance of the capacitor. To address these issues, an inorganic-organic bilayer protective layer (ZnO@RS@Zn) has been introduced on the zinc anode's surface, integrating the advantages of both inorganic and organic protective layers. This bilayer structure not only promotes the uniform deposition of zinc ions but also significantly reduces the occurrence of side reactions. Moreover, it effectively enhances the zinc ion migration rate and the desolvation process. And the presence of a double protective layer has a more excellent desolvation ability. The ZnO@RS@Zn anode exhibits good compatibility with the activated carbon cathode, enabling the ZnO@RS@Zn//AC capacitor to achieve an energy density of 52.67 Wh kg^-1 and a power density of 160 W kg^-1. Additionally, even after 10,000 cycles, the capacitor can maintain a high specific capacity of 44 mAh g^-1 at 2 A g^-1, thereby improving the long-cycle performance of the zinc anode significantly.