Strong Donor-Acceptor Effect Enables Efficient Polyiodides Confinement and Fast Redox Kinetics Toward Zinc-Iodine Batteries.

Aqueous zinc-iodine batteries (ZIBs) based on iodine (I2) redox conversion suffer from severe polyiodides shuttling and sluggish redox kinetics, leading to poor cycling stability. Herein, we propose a donor-acceptor (D-A) synergetic interaction strategy to enable high-performance ZIBs by employing thiophene-rich covalent triazine frameworks (SCTF-DCT) as an advanced I2 host catalyst. The strong D-A cooperative effect combined with a rich micro-mesoporous structure not only optimizes the polyiodides adsorption but also enhances the conversion kinetics of I2 species. Benefiting from the strong D-A effect, the as-assembled ZIBs with I2 loaded SCTF-DCT (I2@SCTF-DCT) cathode demonstrate exceptional cycling life, exceeding 100,000 cycles with a minimal decay rate of only 0.000198% per cycle. In/ex situ characterizations and theoretical calculations reveal the reversible redox mechanism of I2 species and highlight the significance of the D-A collaborative effect. This work elucidates the mechanisms of adsorption and catalytic conversion of I2 species via a D-A synergetic interaction strategy, providing a promising approach for designing advanced host catalysts for next-generation ZIBs and other energy storage systems.