Supramolecular Crystals based Fast Single Ion Conductor for Long‐cycling Solid Zinc Batteries

Abstract The solid polymer electrolytes (SPEs) used in Zn‐ion batteries (ZIBs) have low ionic conductivity due to the sluggish dynamics of polymer segments. Thus, only short‐range movement of cations is supported, leading to low ionic conductivity and Zn 2+ transference ( t Zn 2+ ). Zn‐based supramolecular crystals (ZMCs) have considerable potential for supporting long‐distance Zn 2+ transport; however, their efficiency in ZIBs has not been explored. The present study developed a ZMC consisting of succinonitrile (SN) and zinc bis (trifluoromethylsulfonyl) imide (Zn(TFSI) 2 ), with a structural formula identified as Zn(TFSI) 2 SN 3 . The ZMC has ordered three‐dimensional tunnels in the crystalline lattices for ion conduction, providing high ionic conductivities (6.02×10 −4 S cm −1 at 25 °C and 3.26×10 −5 S cm −1 at −35 °C) and a high t Zn 2+ (0.97). We demonstrated that a Zn‖Zn symmetrical battery with ZMCs has long‐term cycling stability (1200 h) and a dendrite‐free Zn plating/stripping process, even at a high plating areal density of 3 mAh cm −2 . The as‐fabricated solid‐state Zn battery exhibited excellent performance, including high discharge capacity (1.52 mAh cm −2 ), long‐term cycling stability (83.6 % capacity retention after 70000 cycles (7 months)), wide temperature adaptability (−35 to 50 °C) and fast charging ability. The ZMC differs from SPEs in its structure for transporting Zn 2+ ions, significantly improving solid‐state ZIBs while maintaining safety, durability, and sustainability.