In Situ Electrochemically‐Bonded Self‐Adapting Polymeric Interface for Durable Aqueous Zinc Ion Batteries

Abstract The implementation of aqueous zinc ion batteries (AZBs) is hindered by the notorious Zn dendrite growth and side reactions on Zn anodes. Herein, a novel strategy is introduced to overcome these hurdles by designing a self‐adapting soft polymeric composite interface (SAP). Unlike conventional methods relying on passive coating process, the approach leverages dynamic in situ electrochemical bonding via Zn─O interactions formed during cycling, ensuring intimate contact between the SAP interface and Zn electrode. The SAP interface boasts a robust network of hydrogen bonding and electrostatic interactions, which not only promotes the desolvation of Zn 2+ and the repulsion of SO 4 2− , facilitating uniform and rapid Zn 2+ migration while effectively suppressing parasitic reactions; but also exhibits remarkable self‐adapting and self‐healing capabilities, enabling the interface to accommodate volume changes and repair mechanical failures over prolonged cycling. Consequently, highly reversible Zn electrodes are achieved with SAP, showcasing 3300 h at 1 mA cm −2 /0.5 mAh cm −2 and 350 h at 20 mA cm −2 /10 mAh cm −2 in the symmetric cells. The advantages of the SAP interface are further verified when paired with high mass loading LiMn 2 O 4 cathodes in AZBs. The versatile SAP interface offers insights into advanced interface design for efficient and durable AZBs.