Dual-Functional Porous Carbon Spheres Enabling Concurrent Confinement and Chemisorption of Iodine for Shuttle-Suppressed Zn-I₂ Batteries

Aqueous zinc–iodine batteries are receiving increasing attention owing to their high theoretical capacity, abundant raw materials, and environmental friendliness. However, their practical applications are hindered by the shuttle effect caused by soluble intermediates. In this study, we focused on the synthesis of oxygen-functionalized porous carbon spheres (OPCS), via a hydrothermal method coupled with KOH activation, as efficient hosts for iodine. A microporous network with a high specific surface area and a rich array of hydroxyl groups was formed on carbon spheres using KOH. The specific structure enables high iodine loading, confined migration effect of iodine and polyiodides, and intensified chemisorption of polyiodides. The as-assembled zinc–iodine battery with an OPCS/I 2 cathode demonstrated a specific capacity of 162 mAh g -1 at 0.1 A g -1 and maintained 82% capacity after 5000 cycles at 1 A g -1 , showcasing excellent rate performance and cycling durability. This study presents a facile and cost-effective shuttle-suppressing host material achieved through engineering the pore structure and functional groups, offering foundational insights into the rational design of high-performance electrode materials in zinc–iodine batteries.