In-situ crosslinked Zn2+-conducting polymer complex interphase with synergistic anion shielding and cation regulation for high-rate and dendrite-free zinc metal anodes

Aqueous Zn ion batteries hold great promise for next-generation energy storage systems. However, the uncontrolled Zn dendrite growth and adverse side reactions severely hinder their commercial application. Herein, a mixed organic electronic/ionic conductor interface consisting of Zn2+ crosslinked poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (ZPS) is in-situ formed on Zn metal surface, which can be used as a “cation–anion regulation” synergistic interface to protect Zn anodes. It is found that the ZPS interfacial layer has abundant negatively charged sulfonic groups and merit of cation permeability, which enables deanionization shock and effectively alleviates the side reactions. Density functional theory (DFT) calculations and finite elements method demonstrate that the ZPS interfacial layer prevents the local agglomeration of Zn2+ ions and makes the interfacial electric field evenly distributed, thereby enabling uniform Zn2+ flux and dendrite-free deposition. As a result, the modified Zn anode delivers an ultralong Zn plating/stripping cycling lifetime of 2200 h at 1 mA cm−2 and 1 mAh cm−2. Additionally, a long-term lifespan of 250 h is harvested even at an extremely high current of 20 mA cm−2. This work opens up a new field for the mixed organic electronic/ionic conductor in Zn anode protection and offers a promising strategy to accelerate the development of aqueous battery systems.