Unveiling the Role of Cationic Pyridine Sites in Covalent Triazine Framework for Boosting Zinc–Iodine Batteries Performance

Abstract

AbstractRechargeable Zinc–iodine batteries (ZIBs) are gaining attention as energy storage devices due to their high energy density, low‐cost, and inherent safety. However, the poor cycling performance of these batteries always arises from the severe leakage and shuttle effect of polyiodides (I3– and I5–). Herein, a novel cationic pyridine‐rich covalent triazine framework (CCTF‐TPMB) is developed to capture and confine iodine (I2) species via strong electrostatic interaction, making it an attractive host for I2 in ZIBs. The as‐fabricated ZIBs with I2 loaded CCTF‐TPMB (I2@CCTF‐TPMB) cathode achieve a large specific capacity of 243 mAh g−1 at 0.2 A g−1 and an exceptionally stable cyclic performance, retaining 93.9% of its capacity over 30 000 cycles at 5 A g−1. The excellent electrochemical performance of the ZIBs can be attributed to the pyridine‐rich cationic sites of CCTF‐TPMB, which effectively suppress the leakage and shuttle of polyiodides, while also accelerating the conversion reaction of I2 species. Combined in situ Raman and UV–vis analysis, along with theoretical calculations, clearly reveal the critical role played by pyridine‐rich cationic sites in boosting the ZIBs performances. This work opens up a promising pathway for designing advanced I2 cathode materials toward next‐generation ZIBs and beyond.