Catalysis–Deposition Synergistic Strategy to Boost Iodine Redox Kinetics for High-Performance Zinc–Iodine Batteries

Regulating the structure of carbon-based electrodes to enhance their interaction with iodine species and fundamentally understand the underlying mechanism is crucial for fabricating high-performance zinc–iodine batteries. In this work, density functional theory (DFT) calculations reveal that coordination effects among pyridinic N sites in the carbon matrix can promote polyiodide ion dissociation. N-rich hierarchical porous carbon (NPC) was synthesized to leverage the catalysis–deposition mechanism and suppress the shuttling behavior of triiodide ions (I3–). The combination of high-content pyridinic nitrogen sites and abundant pore structures confines the catalytic conversion and adsorption–deposition processes of iodine species within the same microregion, thereby enhancing the suppression of polyiodide ion shuttling. Consequently, Zn–I2 batteries derived from I2@NPC-2 deliver an outstanding specific capacity of 223 mAh g–1 and remarkably retain 85% of this capacity after 50,000 cycles at 50 C, despite a high iodine proportion of 75 wt %. Furthermore, a pouch cell with a high areal iodine loading (20 mg cm–2) maintains a substantial capacity of 172 mAh g–1 after 200 cycles. These findings deepen the understanding of the interfacial interaction between I3– and carbon-based electrodes and provide guidance for the design of high-performance Zn–I2 batteries.