Carbonized polymer dots with intelligent recognition and dynamic protection for highly stable Zn-ion batteries.

Electrolyte additives play a critical role in enhancing the performance and extending the lifespan of zinc-ion (Zn) batteries (ZIBs). However, it remains a great challenge to design intelligent additives that can autonomously regulate the electrolyte structure and realize dynamical protection for the zinc (Zn) anodes. In this study, a novel kind of smart fluorinated and nitrogen-doped carbonized polymer dots (FNCPDs) is synthesized as multifunctional additives for ZIBs. FNCPDs interact with Zn and water molecules through coordination and hydrogen bonding, thereby effectively modifying the Zn solvation structure and suppressing water activity. Especially, the co-deposited FNCPDs form a dynamic protective layer, mitigating water-induced side reactions and inducing Zn plating along the (002) plane during Zn plating. Notably, FNCPDs can detach from the Zn anode during stripping, continuing to regulate solvate Zn and limit water activity. In addition, FNCPDs promote a thin solid electrolyte interphase (SEI) formation and suppress dendrite growth during cycling. The Zn||MnO full cell with FNCPDs electrolyte maintains a high discharge capacity of 164.12 mAh g after 1200 cycles, with a capacity retention of approximately 85.65 %. This strategy highlights the significant potential of environmentally friendly, low-cost carbon dots for application in the field of energy storage.