Engineering Integrated Tandem‐Structured Hosts to Achieve High‐Loading and Ultra‐Cycling Aqueous Zn–I 2 Batteries

ABSTRACT Practical application of high‐load iodine cathodes in zinc‐iodine batteries encounters challenges related to polyiodide shuttling and sluggish iodine redox kinetics. Overcoming these issues requires the development of advanced host materials capable of trapping polyiodides and enhancing Zn‐I 2 redox reactions. In this regard, we incorporated ultrafine silver nanoparticles into a N‐doped mesoporous carbon fiber framework (Ag@CMFs), thereby constructing an integrated tandem‐structured host that leverages an “Integrated Spatial Confinement‐Chemical Anchoring‐Conductive Network” synergistic effect to accelerate the catalytic conversion and adsorption of polyiodides. The host effectively immobilizes all iodine species (I 2 /I − /I 3 − /I 5 − ) on the electrode surface. Benefiting from the synergistic merits of the host, the Ag@CMFs/I 2 cathode (high iodine loading: 14.72 mg cm −2 ) delivers reversible capacities of 208.1 mAh g −1 at 1 C and 180.6 mAh g −1 at 10 C, with Coulombic efficiency maintained above 99.5%. Furthermore, exceptional cycling stability is demonstrated with an impressive capacity retention rate of 80.7% after 92 000 cycles at 50 C. The pouch cell delivers an areal capacity of 6.5 mAh cm −2 and remains stable for over 300 cycles with an ultrahigh iodine loading of 3200 mg. This study offers fresh perspectives on host architecture to prevent polyiodide shuttle behaviour and guarantee long‐lasting cycle stability of Zn–I 2 batteries.