Extending Cycling Life Beyond 300 000 Cycles in Aqueous Zinc Ion Capacitors Through Additive Interface Engineering

Abstract Developing low‐cost and long‐cycling‐life aqueous zinc (Zn) ion capacitors (AZICs) for large‐scale electrochemical energy storage still faces the challenges of dendritic Zn deposition and interfacial side reactions. Here, an interface engineering strategy utilizing a dibenzenesulfonimide (BBI) additive is employed to enhance the stability of the Zn metal anode/electrolyte interface. The first‐principles calculation results demonstrate that BBI anions can be chemically adsorbed on Zn metal. Meanwhile, the experimental results confirm that the BBI‐Zn interfacial layer converts the original water‐richelectric double layer (EDL) into a water‐poor EDL, effectively inhibiting the water related parasitic reaction at the electrode/electrolyte interface. In addition, the BBI‐Zn interfacial layer introduces an additional Zn ions (Zn 2+ ) migration energy barrier, increasing the Zn 2+ de‐solvation activation energy, consequently raising the Zn 2+ nucleation overpotential, and thus achieving the compact and uniform Zn deposition behavior. Furthermore, the solid electrolyte interphase (SEI) layer derived from the BBI‐Zn interfacial layer during cycling can further maintain the interfacial stability of the Zn anode. Owing to the above favorable features, the assembled AZIC exhibits an ultra‐long cycling life of over 300 000 cycles based on the additive engineering strategy, which shows application prospects in high‐performance AZICs.